Pests, Diseases and Weeds

Transcription

1 Pests, Diseases and Weeds Level 3 Copyright P.O. Box 461, Hillcrest, 3650 (031) Title: Monitor Pests, Diseases and Weeds on Crops Applied Title: Monitor Pests, Diseases and Weeds on Field: Agriculture and Nature Conservation Sub-Field: Primary Agriculture SETA (SGB): AgriSETA Skills Area: Pests, Diseases and Weeds Context: Production US No: Credits: 2 Author: Cabeton Training and Development et al Notional Hours: 20 Based on the Production Guidelines of: Supported by:

2 Table of Contents Directions... 4 Introduction Purpose Learning Assumed to Be in Place Prescribed Material... 5 Revision of Level Common Pests in Production Common Diseases in Production Common Weeds in Production Scouting... 7 Chapter Introduction Good Agricultural Practice Damage Symptoms Scouting and Sampling Procedures Fruit Fly Infestation Assessment Correct vs. Incorrect Protocols during Pest Collection and Analysis Observation and Recording of Pests and Predators Scouting categorisations The Difference between Pests and Predators Pest Monitoring and Scouting Deciding when to scout Scouting Methods Data Tree Method Diagonal Method Inspection Points or Units on a Tree Reporting Methods Trapping Unknown Pests for Identification The Importance of Identifying Unknown Pests Methods of Dealing with Unknown Pests Recordkeeping Chapter Introduction Different Types of Traps: Pheromone Traps Sticky Traps Pit-fall traps Trapping with colour and light Assessing Traps Monitoring Techniques Monitoring of Diseases and Weeds Recordkeeping Pest Data Chapter Introduction - The impact of disease on production and profitability Monitoring Disease symptoms in A list of known diseases and their symptoms The protocols surrounding disease prevention in The protocols for dealing with the outbreak disease in Phytophthora foot rot can best be controlled by preventative practices, including use of resistant rootstock and planting in well-drained land Budding seedlings high, avoiding wounds, and keeping soil off the lower trunk are among recommended control practices. Soil fumigation of seedbeds should be practiced in field nurseries

3 Chapter Introduction to weeds and their impact on Agriculture in General and production specifically Monitoring plans for weed eradication in line with Good Agricultural Practice Advantages of monitoring plans related to weed control Implementation and actions related to weed monitoring plans Survey and mapping Listing resources and select control methods Planning monitoring operations related to weed control Implementation of monitoring operations related to weed control Record keeping related to the monitoring of weeds Monitoring and reporting protocols related to unwanted plant growth (weeds that are not necessarily invasive species) Monitoring and reporting protocols for Invasive species A list of frequently occurring invasive species for farms New or unknown plant species observed during weed monitoring actions Bibliography

4 Directions This learning material has been developed to assist the learner wishing to complete this unit standard. The guide contains all necessary learning to ensure that the learner will attain the competencies required by the unit standard. The learner guide is accompanied by a Learner Assessment Guide. Please ensure that you have access to this guide as well. The learner guide was designed to be used by a learner during the presentation of a skills program based on the unit standard, and to be kept afterwards by the learner for reference purposes. The learner assessment guide was designed to be completed during and after the presentation of the skills program, and forms part of the assessment process. Although this learner guide contains all the information required for attaining competency in this unit standard, references to additional resources, both printed and electronic, are provided for further study by the learner. Information in boxes is indicated by tags that show: 4

5 Introduction 1. Purpose A learner achieving this standard will be able to recognize, monitor and apply basic control of insects, plant diseases and common weeds, in a specific agricultural enterprise. In addition they will be able to report their findings to management or advisors. Learners will gain an understanding of sustainable agricultural practices as applied in the animal-, plant and mixed farming sub fields. This unit standard focuses on the application of pest control practices in primary agriculture. They will be able to participate in, undertake and plan farming practices with knowledge of their environment. This unit standard will instil a culture of maintenance and care for both the environment as well as towards farming infrastructure and operations. 2. Learning Assumed to Be in Place It is assumed that the learner has successfully completed the unit standards listed below: NQF Level Unit Standard Number 2 Literacy and Numeracy Prescribed Material The following material is prescribed for this unit standard: Unit Standard Description Demonstrate a basic understanding of the physiological functioning of the anatomical structures of a plant Control pests and diseases ad weeds on crops effectively and responsibly. Identification Manual for Pests and Their Natural Enemies published by Research International Contact Details: (013) or 5

6 Revision of Level 2 1. Common Pests in Production The main impact of pests and diseases on commercial citrus production is damage to trees that may lead to lower yields and poorer quality fruit, damage to fruit that may render it non-exportable and the presence of phytosanitary pests and diseases that may lead to export rejections. All insects are not pests. Pests are those insects which reduce or damage the crop quality and quantity. Beneficial insects assist in pest control through predatory or parasitic behaviour. Insects damage plants by sucking, stinging or chewing the plant parts, laying eggs on or in plant parts, damaging the surface of fruit when moving over it, causing access points to other pests or diseases, or by acting as a vector for other diseases. Numerous control measures exist for controlling pests, including chemical sprays, systemic chemicals, beneficial insects, and traps. Chemical spays are not the only option for controlling pest populations. 2. Common Diseases in Production Diseases in citrus are detected through the presence of their symptoms. Diseases are caused by micro-organisms, such as bacteria, viruses and fungi. Fungi grow on the plant parts and are more likely to occur in humid conditions. Viral diseases destroy their host and prevention is the only means of control. Bacterial diseases spread very rapidly and are very difficult to control. The most common disease symptoms are wilting, discolouration, gum formation and dieback of plant parts. diseases are classified as fruit and foliar diseases, soil-borne diseases, and graft-transmissible diseases. 3. Common Weeds in Production Weeds are any plants that are not wanted in the area where the citrus crop is produced. Invasive plants are plants that come from a different country or area and that have no natural enemies in the specific area. Invasive species pose a threat to ecosystems and can cause the decline of natural vegetation and beneficial organisms. Invasive plants have been categorised by the Botanical Society of South Africa and the ARC into three categories. 6

7 Category 1 plants have to be removed wherever they are found and category 3 plants are the least threatening. Weeds and invasive plants can be controlled through manual or chemical actions or through the introduction of biocontrol agents. Weed germination can be suppressed through the use of mulch or cover crops. 4. Scouting Scouting means observing orchard and plant conditions in order to gain information about the visible signs and symptoms of pests and diseases. Scouts must have excellent vision and a positive attitude to their job, and they must be well trained to understand the principles of scouting so that results are not biased. A formal scouting strategy is required for each production unit, and should include all the necessary procedures including reporting and recordkeeping procedures. Scouting procedures normally include selecting permanent data trees, unit inspections, pest traps, cursory examinations, and recordkeeping and reporting. Old damage refers to damage that was caused before by pests and diseases that have probably already been eradicated and new damage refers to new injuries to plants that are caused by a new outbreak of a pest or disease, which should be identified and dealt with. Certain symptoms occur at specific points in the production cycle or at a specific time of the year. Recordkeeping of pest and disease populations, damage found and actions taken will assist in active pest and disease control. Recordkeeping of climatic conditions and the developmental stages of the plant aid in predicting the occurrence of pests and diseases. Threshold values indicate the pest density at which suppression measures should be implemented in order to prevent the pest population from reaching the economic injury level. Pest Organisms In agriculture, pest organisms are organisms that cause damage to livestock, crops, humans, or land fertility, for instance tsetse fly, fruit fly and malaria mosquitoes. pests are organisms whose feeding and / or reproductive habits lead to a reduction in the quantity and quality of the citrus fruit produced. Beneficial Organisms In agriculture, beneficial organisms are organisms that contribute positively by their habits, for example by feeding on pest organisms or by pollinating flowers to enable fruit development. Vector A vector is an organism, such as an insect, that transmits disease-causing micro organisms from infected plants to other plants. 7

8 Plant Disease A plant disease can be described as an impairment of the plant s functions through organisms such as fungi, bacteria or viruses. Weeds Weeds is the generic word for plants growing in a place where they are not wanted. Weeds become important in commercial farming when they damage crops or poison domestic animals. Alien Plants Alien plants are plants that originate from other countries or areas. Alien plants were brought to this country or region for economic or ornamental reasons. Invasive Plants Invasive plants are alien plants that have become harmful to the natural ecosystem. Not all alien plants are invasive in South Africa only 2.5% of plants that are introduced become invasive. Invasive plants do not have natural enemies or other limitation on their growth. They tend to overrun ecosystems that they are introduced into. Invasive plants are a major threat to biodiversity and ecosystem stability. Scouting Scouting means observing orchard and plant conditions in order to gain information about the visible signs and symptoms of pests and diseases. It involves looking at strategic positions in orchards and recording pest numbers, disease symptoms. 8

9 Chapter 1 After completing this chapter, the learner will be able to: Monitor the common pests prevalent in the specific agricultural enterprise. Collect insects not familiar and that had been identified. 1. Introduction Scouting, or monitoring pest populations, is part of an integrated pest management (IPM) system. According to the principles of IPM, one should scout for specific pests periodically and monitor the increase in population by gathering specific types of data and samples. It is recommended that the data that is gathered be analysed by an expert in pest and disease control. The expert should then try to find a responsible and suitable method of controlling pests and diseases. IPM principles require that all alternative pest control methods are considered, with chemical pesticide application as a last resort. In some cases, IPM prescribes treating only the portions of a farm or orchard where higher than threshold levels of pests have been found, rather than treating the whole farm resulting in using less chemical plant protection products. Integrated Pest Management An approach to pest control that includes biological, mechanical and chemical control methods. The goal of IPM is to produce a healthy crop in an economically efficient and environmentally sound manner. The benefits of scouting and continuous monitoring of pests and diseases and the analysis of the data that is gathered are as follows: Recognise damage done by pests and symptoms of diseases early enough to react against it. Enabling recordkeeping of the appearance of pests and diseases. If you analyse data over a period of time, patterns and cycles appear. This means that you can be better prepared and can ensure that certain pest populations are controlled pre-emptively. Assisting in future planning for the management and control of pests and diseases. Monitoring the efficacy of control measures against pests and diseases. Pests often develop a resistance to one method of pest control. If the pest population is monitored before and after control actions, you will immediately note if such a resistance develops. Prevent the spread of pests and diseases to other orchards or the surrounding farms or environment. 2. Good Agricultural Practice Good agricultural practices are basic environmental and operational conditions that are necessary for the production of safe, wholesome fruit. The term includes practices used in growing, harvesting, sorting, packing and storage operations, as well as pest, disease and weed control. Good Agricultural Practices 9

10 (GAP) is prescribed by the legislation and all citrus growers are compelled to adhere to these prescriptions. The application of integrated pest management forms part of GAP. Overseas markets require accreditation to international GAP schemes such as GlobalGAP and EurepGAP before producers are allowed to export fruit to these countries. GAP principles in terms of pest scouting and monitoring require scouting for pests and diseases according to specific procedures at set intervals. The objective is to react against pests and diseases in time to prevent the spread of the pest or disease and to limit the amount of damage that it does to the crop. 3. Damage Symptoms The CRI Identification Manual for Pests and Their Natural Enemies is one of the most important tools that a scout needs. It provides pictures and descriptions of all the citrus pests and of disease symptoms, which allows a scout to identify the presence of the pest or disease in the orchard. It is important to distinguish between old damage and new damage caused by pests. The distinction between old and new damage was discussed in detail in the level 2 guide. Repeated scouting in the same orchard by the same scout, and detailed recordkeeping assist in identifying new damage. Identify the plant part on which the damage is most visible and use the tables below to determine what pest or disease caused it. Plant Part Symptom or Damage Possible Causes Fruit Abnormal shape Budmite Bollworm Lesions or marks Fallen fruit Residue Visible insects Prematurely coloured or discoloured Red Scale Thrips Bollworm Brown leafhopper Green leafhopper Wind Hail False codling moth Fruit fly Budmite Bollworm Alternaria Burst Mealy Bug Aphids Australian bug Mealy Bug Aphids Australian Bug Foliage Malformation Budmite Aphids Thrips False coddling moth Fruit fly Leafhopper Mites Alternaria Residue Mealy bug 10

11 Plant Part Symptom or Damage Possible Causes Feeding marks Discolouration Visible insects Aphids Australian bug Leafminer Orange dog butterfly Thrips Grasshopper Red scale Mites Leafhoppers Leafhoppers Mealybug Australian bug Soft brown scale Mites Blossoms Abnormal blossom shape Budmite Insects present on blossoms Bollworm Aphids Residues on blossoms Aphids Table 1.1: Pest Damaged Plant Parts and Possible Causes Table 1.2 indicates identifying features of specific insects. Identifying Feature Flying insect Sedentary insect (not moving) Beetle Caterpillar Options False coddling moth Fruit fly White fly Brown leafhopper Green leafhopper Orange dog butterfly Mealy bug Australian bug Red scale Aphids Soft brown scale Tip Wilter Ladybird Stink bug Orange dog Bollworm Very small insect Thrips Green leafhopper Mites Table 1.2: Identifying Features of Insects Table 1.3 indicates the months of the year in which specific insects occur most frequently. This information has been compiled form data analysis and recordkeeping and it can assist you further in identifying the pest insects found in the orchard. 11

12 January February March Red scale on the fruit, Mealybug, Mites (Especially Rust Mite), Thrips, Ants, Psylla, Aphids Mites, Red scale, Mealybug, Ants, Psylla, Aphids False Codling Moth, Red scale, Mealybug, Fruit Fly, Ants, Psylla, Aphids April May June Ants, Psylla, Aphids Ants, Psylla, Aphids Ants, Psylla, Aphids Ants, Psylla, Aphids July August September Thrips on the leaves, Ants, Psylla, Aphids Thrips (leaves and fruit), Bollworm, Red scale (twigs), Ants, Psylla, Aphids October November December Thrips (fruit), Red scale (fruit & twigs), Mealybug, Bollworm, Ants, Psylla, Aphids Table 1.3 Pest Occurance Months 4. Scouting and Sampling Procedures Thrips (fruit), Red scale (fruit & twigs), Mealybug, Ants, Psylla, Aphids Thrips (fruit), Red scale (fruit & twigs), Mealybug, Mites, Ants, Psylla, Aphids To manage pests successfully, the problem pest must be identified correctly. It would be pointless and expensive to apply the wrong type of pest control action. The most effective way to identify pests is simply to walk around and actively scout or look for pests in the orchard. Scouting is not just aimless wandering and looking around but must be a structured and regulated approach to monitoring the occurrence of pests. pest scouts are well trained individuals who search and scout with very specific goals in mind. In order to recognise the emergence of a pest population, two different facets must be concentrated on during scouting: You will actively look for a specific pest, or You will actively look for damage to the fruit, leaf or blossom, or plant parts that would be caused by a specific type of pest. The findings of a scout need to be well documented and reported as part of the larger pest monitoring program. It is thus important that scouts are trained carefully in both the recognition of specific pest populations, as well as the recording of the necessary data that will make the information valid and valuable. The following types of pests are considered phytosanitary pests. The occurance of these pests should be monitored, specifically: fruit fly false codling moth mealy bugs The presence of phytosanitary pests in the orchard can lead to huge losses and have to be monitored and controlled on a regular basis. In terms of Good Agricultural Practice it is important to keep scouting records that will confirm counts of other pests such as red scale, thrips, leafhopper and leaf-miner as well as phytosanitary pests. Remember that not all pests occur in all geographical or production areas. It is vital to familiarise yourself with the prevalent pests that are a problem in the area where your farm is situated. The following records must be kept in good order and be available at all times for official inspection or on request: Trap counts. 12

13 Dates when lures are hung and changed. Volumes of bait sprays. Products used in the baits. Active ingredient of chemical products used. Records of minor pests must be kept. Monitoring include the knowledge of economic threshold or action levels and the control options chosen if above the economic threshold or action levels are reached. The Department of Agriculture will inspect orchards earmarked for selected export markets to issue a phytosanitary certificate. The producer is responsible to keep records concerning the status of pests and any chemicals or other measures used to control pests. Below follows a detailed example of the guideline for the monitoring of Fruit Fly presence in the orchard. This kind of guideline is also sometimes called a protocol. The following is an example used as a guideline in the Vaalharts area: Fruit Fly Infestation Assessment Monitoring o Weekly monitoring of fruit fly from February. o Make a note of any activity noticed concerning both species Mediterranean - and Natal Fruit Fly and both sexes, male and female. o Hang out of traps in week 5 of the production cycle. That is before colour break. o Change lures and dichlorfos blocks in traps in week 12,19, and 26 for the whole area and week 34 for Valencia orchards. Product To Use - Compulsory o The use of Questlure traps are recommended by government legislation. o One trap for every 6 ha of should be used. o Traps must be placed more than 50 meters apart. o Change traps every 7 weeks until the harvest has been completed. o M3 traps must be hanged out in week 5. o M3 control effective for 4 months. o M3 is a perishable product and can only be used in one season and not kept for the next season. Product to use Recommended o In addition to the Questlure, Capilure attractants are recommended by government. o In Vaalharts only the use of Questlures are compulsory, thus avoiding a confusion of traps, counts of male and female flies and time of spraying. Economic threshold o One female fly per week per trap in Questlure is acceptable. o The economic threshold is reached if there is two flies or more per week in the trap. o As the Questlure catches mostly female flies, you do not have to identify the sex of the flies. Control options Cultural control Biological control Chemical control o Orchard sanitation weekly o There is no virus or o Protein Bait : 250 ml 13

14 o o Bugweed (weeds with berries or fruit) should be removed within 100m of citrus orchards After harvesting, all remaining fruit must be stripped and be disposed of. parasites at this stage to treat fruit fly infestations. o o o o o Buminal or 400ml Hymlure in 100 litres of water ml per tree Mantis or Ladybird applicator. The protein is concentrated 15 times to 6ml per 100ml water as only 45 ml bait is applied per sprayed tree. Bait before it gets hot. The toxicant concentration must never be increased. This remains as 50 g of Dipterex or 175 ml Malathion EC or 300g Malathion WP per 100 litres of water o The harvest interval is 28 days if Dipterex is used and 7 days for other chemicals. o Spray orchards after harvesting once or twice for fruit fly 5. Correct vs. Incorrect Protocols during Pest Collection and Analysis Scouting is a vital part of a farm s IPM program. Scouting involves systematically moving through orchards looking for pests, measuring populations, and then using this information to make pest control decisions. The information helps growers determine if a pest control treatment is needed, where it s needed, and what options are available and practical. IPM principles refer to economic thresholds. Economic thresholds refers to the cost of the pest damage weighed against the cost of the pest treatment, this comparison is used in the decision-making process. This information can be helpful when deciding whether or not a pest situation warrants treatment. IPM can help a pest suppression program. Potential problems often are identified early and managed, thereby reducing the control costs and crop losses. Since pest populations vary, spraying without scouting first may result in unnecessary or insufficient pesticide applications. A grower can use pesticides more effectively by knowing what pest is in a field and treating it accordingly. When scouting for insects, it is important to get a random sample. However, the scout also needs to observe and note any high population areas in the orchard. The decision to spray is never one that can be taken lightly. Not only is the cost of any chemical application high but the effect that pesticides can have on the environment must also be considered. Spraying must be the last option available to a grower before it is used. In order to make an informed decision a grower needs as much information as possible concerning the presence of pests and diseases in the orchard. A grower must also know where these pests and diseases occur to ensure that non-infected areas are not treated and money thereby wasted. Pests control decisions must never be based on historical data. Spraying must only be done after the presence of pests and diseases have been physical confirmed by a thorough, structured, well implemented and recorded monitoring, scouting and trapping plan. 6. Observation and Recording of Pests and Predators 14

15 As discussed previously, the pest scout has to actively inspect orchards on an ongoing basis and keep record of the findings. Pests that are found must be collected and identified. Insect identification can be achieved through referring to the Identification Manual for Pests and their Natural Enemies published by Research International - CRI Scouting categorisations All pests are categorised according to very specific categories for scouting purposes. These pests are also each identified by a specific scouting symbol. This means that this is the symbol that the scout should write down or record on the scouting sheet when they encounter such a pest. Table 1.4 below is a list of all the pests and their scouting symbols that are important for, as is identified in the CRI manual. Scale Lepidoptera Homoptera Mussel Scale MS Bollworm BW Australian Bug Red Scale RS Leafhoppers LR Leafhoppers LH Circular Purple Scale PS butterflies Soft Scales SS looper or measuring worm Waxy Scale WS False codling moth Powdery Scale AS Black Scale BS AB OD Aphids AP MW Psylla CP FCM Mealybug MB Mites: Snails: Sundry pests: Grey mite GM Brown snail BS Ants A Budmite BM Dune snail DS Thrips T Lowveld citrus mite (Oriental mite) Flat mite PM Rust mite RM Red spider mite LM Tower snail TS Fruit flies FF RSM Silver mite SM red RM mite Table 1.4 List of Pests and Scouting Symbols It is important to know that all insects found in the orchards are not pests. The natural enemies of the main pests of citrus are listed in the Identification Manual for Pests and their Natural Enemies of the CRI. 15

16 There is an increasing interest in attracting predators to the orchards or placing specially bred predatory organisms in the orchards. This practice can effectively control the outbreak of pests and diseases in an controlled manner and not cause any harm to the environment. During pest and disease monitoring, it is also important to scout for the known predators. If the predator count is sufficiently high, chemical action might not be necessary The Difference between Pests and Predators Pests affect the plant negatively while predatory insects or organisms feed on or do damage to these pests. The most important predatory organisms for citrus are listed below in table 1.5. Host (The pest) Organism (Predator) Mealybug Red scale, circular purple scale, mussel scale Soft scales Red Scale Mealybug Red scale, circular purple scale Red scale Red scale, mealybug, psylla, aphids, mites Mealybug Thrips, mite pests Mealybug, scale, aphids, occasionally mites Circular purple scale, Red scale Australian bug Pest mites thrips, lepidopteron eggs, mites, possibly scale crawlers Table 1.5 Pests and Predators Anagyrus (Parasitic wasp) Aphytis (Parasitic wasp) Coccophagus semicircularis Comperiella bifasciata (Predatory wasp) Coccidoxenoides (Small wasp) Chilocorus distigma (Ladybird) Chilocorus nigritus (Ladybird) Chrysoperla pudica (Green lacewing) Cryptolaemus montrouzieri (Ladybird) Euseius spp (Predatory Mite) Exochomus spp (Predacious ladybird) Lindorus lopanthae (Predatory beetle) Rodolia spp (Vedalia beetle) Strethorus spp (Strethorus beetle) Orius thripoborus (Predatory bug) 7. Pest Monitoring and Scouting 7.1. Deciding when to scout Choosing the right time to scout is often determined by analysing past scouting and monitoring records. There is also a wealth of information available from scientific research bodies and plant improvement programs that will advise scouting times determined by past experience with a pest, crop growth stage, or using models that predict the timing of pest occurrence. Commonly the occurance of pests specific to the area where the farm is based and when those pests normally occurs will determine when scouting will be done Scouting Methods 16

17 There are two scouting methods commonly used in the Industry, the data tree method and the diagonal method Data Tree Method Specific, representative trees evenly distributed throughout the orchard are selected and marked. These trees are inspected on each occasion that scouting is conducted. The advantage of this method is that the trees to be inspected are easily identifiable within the orchard and that the same tree is visited each time. In this way a history of the pest status of the orchard and specific trees is built. Figure 1 Data tree method representation as seen from the top of an orchard Diagonal Method A diagonal line is selected and the scout moves through the orchard examining trees at various points, for example, tree number 1, row 1 then tree number 3, row 3 and then tree number 5, row 5, etc. The number of trees selected per orchard will depend on the size of the orchard. Research International (CRI) recommends 5 trees per hectare. The number of trees selected will vary from farm to farm depending on what resources are available and what is practical. The greater the number of trees inspected, the more accurate scouting data will be. Figure 2 The diagonal method representation as seen from the top of an orchard 7.3. Inspection Points or Units on a Tree An inspection point or unit is the branch, fruit, fruit cluster, leaf or leaf flush examined during the scouting procedure at a specific position on the tree. What you will examine at the inspection point will 17

18 depend on the time of year and the pest that you are looking for. The recommended method is to select 10 inspection points per tree, 2 on each side of the tree and 2 points inside the tree. See a detailed example of the inspection points in Fig. 3 below. Figure 3 Suggested inspection points on citrus trees 8. Reporting Methods Effective pest control requires keeping careful records of pests observed during scouting of orchards, and actions taken to control pests including crop protection products used and other methods aplied. This data is normally recorded in an organised manner on a pre-designed scout sheet. Data from monitoring tools such as sticky traps and pest sighting logs is used in the decision making process, and also to evaluate the success of pest management strategies used. Below follows an example of a completed scout sheet that might be used on a Farm: Name of Pest Scout: Joe K Orchard or Block Number : 7 East Date: 7 March 2010 Time of Day: 07:35 Temperature: 28 C Production Week Number: 6 General Weather Data Information: Overcast and humid, thunderstorms first thing in the morning Mark the trees to be inspected in the Orchard with an X Tree Number 1 2 Row or Inspection Unit Number

19 3 4 Record the information observed on each tree: Row Number Tree Pest Symbol Number Number / s for of this observations Pest Observed 1 4 Nil 0 No pests observed General Information or Notes 1 7 A Too many A lot of Ants Visible to the Eye, but to count no Mealy Bug 1 7 FCM 2 Checked trap placed on Nil 0 No pests observed 2 6 Nil 0 No pests observed 3 4 A Too many A lot of Ants Visible to the Eye, but to count no Mealy Bug 4 2 FCM 1 Checked Trap placed A Too many to count 4 5 MB 7 A lot of Ants Visible to the Eye General Observations and Comments: There is some damage to the bark and lower branches of trees in row 1 (Trees 1 and 2) caused by the wild pigs that broke through the boundary fence on Leaf damage noted on trees 2-5 in rows 2 and 3, looks like necrotic spots and unknown residue. 9. Trapping Unknown Pests for Identification Sometimes during the scouting exercises and through the monitoring process, one might come across new or unknown pests and insects. If a significant number of these pests are observed, or the damage that they cause is of significant concern, then it would be wise to trap some of the insects and have them professionally identified. Trapping insects means attracting the insect by some means and, having attracted it, preventing its escape. Different trapping mechanisms exist. They usually fall into one of the following categories: 19

20 Physical or pitfall traps where the insects are drawn to a food source and trapped or move over a surface and then get trapped when they fall into the trap. Physical traps can also be sticky to ensure that the insect clings to the sticky material when coming in contact with it. Light traps such as ultraviolet lights which draw the insects toward the light. This often also includes electrocuting the insects once they come in contact with the surface of the trap. Pheromone traps which mimics one sex of the insect (usually the females) and draws the males away from the females eliminating mating between the sexes to control pest populations. Information about unknown pests If unknown pests or disease symptoms are observed, then the following organisations can be contacted to assist in identifying the pest and its potential economic impact on the crop. Control mechanisms and recommendations can also be recommended or prioritised by these organisations: Research International Tel Agricultural Research Council Tel The Importance of Identifying Unknown Pests Unknown pests are most likely a sign that a new organism has found its way into the area. In some cases these new organisms might cause economic damage to the crop, and new methods of control might have to be developed. These organisms often come from other areas or other countries and might have no natural enemies to control its population size in that specific area. Especially in terms of vector insects (insects that spread disease) and phytosanitary pests, early detection can ensure early reaction and prevent the pest from spreading to the environment and other orchards or disallowing the crop to be exported Methods of Dealing with Unknown Pests It is important to identify the insect which is unknown accurately and then decide what danger it holds to the citrus crop. All known information about this insect must be gathered, including its anatomy and feeding habits. If it is identified as a pest insect, it should be reported and dealt with immediately. It is recommended that any suspicious unknown insect be reported to such institutions as plant pathology laboratories and research programs. There is always a risk of pests entering an area or invading the country from a different country. Just because it isn t currently listed in the identification manual, does not mean that it is safe to disregard the insect. 10. Recordkeeping IPM requires keeping careful records of pests reported in orchards and surrounding fields or areas, and actions taken to control pests (including pesticides used). Data from monitoring tools such as traps and pest sighting scout sheets or logs, are used in the decision making process, and also to evaluate the success of pest management strategies used. If accurate records are not kept, then unnecessary or wrong pest control actions might be undertaken, which will cause unnecessary chemical residues to the crop and might potentially harm the viability of 20

21 the crop as well as the surrounding environment and negatively affect the profitability of the farming enterprise. Chapter 1 Scouting, or monitoring pest populations, is part of an integrated pest management (IPM) system. According to the principles of IPM, one should scout for specific pests periodically and monitor the increase in population by gathering specific types of data and samples. Good agricultural practices are basic environmental and operational conditions that are necessary for the production of safe, wholesome fruit. Repeated scouting in the same orchard by the same scout, and detailed recordkeeping assist in identifying new damage and determining the cause of the damage. The most effective way to identify pests is simply to walk around and actively scout or look for pests in the orchard. Scouting involves systematically moving through orchards looking for pests, measuring populations, and then using this information to make pest control decisions. During pest and disease monitoring, it is important to scout for known predators. If the predator count is sufficiently high, chemical action might not be necessary. Choosing the right time and to scout and the method of scouting is often determined by analysing past scouting and monitoring records. If a significant number of these pests are observed, or the damage that they cause is of significant concern, then it would be wise to trap some of the insects and have them professionally identified. Data from monitoring tools such as traps and pest sighting scout sheets or logs, are used in the decision making process, and also to evaluate the success of pest management strategies used. Complete activity * and * in the Learner Workbook. 21

22 Chapter 2 After completing this chapter, the learner will be able to: Demonstrate a basic knowledge of trapping, monitoring and recording the incidence of pests, diseases and weeds. 1. Introduction It is not always possible to gain an accurate count of the insect pests in an orchard by observation only as insects might be more active at night or fly around. Trapping can assist the pest scout in gathering more accurate information. Different traps can be set to trap different pests or types of insects. When these traps are checked at set intervals, the numbers of insects found inside the trap are recorded. If recorded numbers exceed a specific count, the threshold value is exceeded and action needs to be taken against these insects. Different traps can also be combined on trap stands to lure and trap different insects and to gain an overall impression of the insect pests present in an orchard. Figure 1 Insect Science trap stand place in rows to trap multiple insect pests 2. Different Types of Traps: 2.1. Pheromone Traps These traps mimics pheromones excreted by females of a specific insect to attract males. In this way it traps the males and disrupts mating, preventing an increase in the population. False Coddling Moth is often trapped and controlled in this manner. 22

23 2.2. Sticky Traps These are traps with either a sticky substance on a piece of card board or a sticky liquid inside a container. These are mostly used to trap flying insects, but insects walking over the surface will also be trapped. The insect cannot escape the sticky surface or liquid once they are attached to it Pit-fall traps This is a trap for catching ground crawling insects, made out of a cuplike container buried in the ground into which insects fall. Insects often trapped in this manner are ants. Figure 2 Simple pitfall trap covered with screening and provided with hanging bait Trapping with colour and light Alternative methods of trapping include placing specific coloured sheets in orchards usually blue or yellow to which the insect are drawn. Although not commonly practiced in agriculture, light traps emitting UV light can also be used to lure insects and then electrocute them. Figure 3 Yellow Bug Sheets These yellow Bug Sheets from Insect Science are placed in greenhouses, shade houses and open fields for the mass trapping of different agriculturally important pests. The yellow sheets are used for Leaf Minors, Whiteflies, Leafhoppers and Thrips. 23

24 3. Assessing Traps Traps are assessed by checking the insects that was trapped. IPM and GAP regulations determine when traps should be checked. The manufacturers of the different types of traps also have recommendations on the frequency when the different types of traps should be assessed for insect activity. Insect found in traps must be identified and recorded. In the case of insects such as fruit flies it is important to record the gender of the insects trapped as well as the presence of certain genders in the orchard have an effect on the decision to treat the orchard chemically or not. 4. Monitoring Techniques When not using traps the only other avenue of monitoring the presence of pests and insects in citrus orchard is scouting. Scouting procedures and processes is discussed in chapter 1. Although a well designed and implemented scouting plan can effectively monitor the occurance of certain pests in the orchard modern day farming practices requires the use of traps to ensure that the presence of all pests and predators in the orchard are identified and recorded. 5. Monitoring of Diseases and Weeds While scouting and assessing traps the scout are also responsible to monitor the orchard for occurrences of diseases and weeds Diseases Diseases are caused by fungi, viruses, bacteria and nematodes and are much more difficult to control than insect pests. By the time disease symptoms are visible, the disease causing organism has already been present for some time and has already multiplied and possibly even spread. For this reason, most diseases present in production are dealt with in a preventive rather than a reactive way. Diseases often destroy the plant or cause so much damage to the plant that it has to be replaced. When plants are replaced, it normally entails great economic expense and lost production time in terms of a crop to sell at profit. The process used to detect and identify diseases is discussed in chapter Weeds Weeds pose many hazards to successful crop production. Weeds compete with citrus trees for nutrients, light, water, space and harbour insects and rodents that attack citrus trees. There are three categories of weeds that should be monitored in citrus orchards, namely broadleaf, grasses, and sedges. The procedures of how weeds are identified, classified and control is discussed in chapter Recordkeeping Records are kept of all monitoring and scouting practices. The most common record in use on a farm where scouting practices and monitoring activities and findings are recorded is the scouting sheet of which an example is given in chapter 1. All records of scouting and trap monitoring procedures must be evaluated and the data recorded. The effectiveness of the IPM is measured against these records. GAP also requires that records are kept and be available for inspection by accreditation and auditing agencies. 7. Pest Data The data collected from scouting and trap monitoring records will determine how pests controlled. By collecting and evaluating data the effectiveness of control measures can be determined as well as the occurance of any new infestations. 24

25 Data must be collected and evaluated on a regular basis. By evaluating data the effectiveness of scouting practices can also be determined and changes to the IPM can be implemented where necessary. Chapter 2 Trapping can assist the pest scout in gathering more accurate information. Different traps can be set to trap different pests or types of insects Traps are assessed by checking the insects that was trapped. IPM and GAP regulations determine when traps should be checked. While scouting and assessing traps the scout are also responsible to monitor the orchard for occurrences of diseases and weeds. Records are kept of all monitoring and scouting practices. The data collected from scouting and trap monitoring records will determine how pests controlled. The data collected from scouting and trap monitoring records will determine how pests controlled. Complete activity * in the Learner Workbook. 25

26 Chapter 3 After completing this chapter, the learner will be able to: Monitor the symptoms of disease associated with the agricultural enterprise. 1. Introduction Diseases are caused by fungi, viruses, bacteria and nematodes and are much more difficult to control than insect pests. By the time disease symptoms are visible, the disease causing organism has already been present for some time and has already multiplied and possibly even spread. For this reason, most diseases present in production are dealt with in a preventive rather than a reactive way. Diseases often destroy the plant or cause so much damage to the plant that it has to be replaced. When plants are replaced, it normally entails great economic expense and loss of production as new trees require time to grow before they produce fruit. Diseased plants can also not be used for propagation purposes. It is thus important to ensure that the trees used during the establishment of an orchard are sourced from a reputable nursery and are certified as disease free. Diseased fruit either decreases the quality of the crop, resulting in inferior prices for the crop, or prevents the crop from being sold, or at the least, exported in the case of the occurance of phytosanitary diseases. 2. Monitoring Disease symptoms in Good disease management requires an in depth knowledge of how different factors interact in the development of the disease; particularly, knowledge of environmental conditions that stress the plant, making it more susceptible to disease. In most cases if you apply this detailed knowledge it will help to prevent a disease problem. However, it is unwise to simply assume that all diseases will be pre-empted and avoided. Regular monitoring is needed to detect diseases as soon as they occur and before they become well established. It is important to report any abnormal appearance or activity of a citrus orchard immediately. Just because the causing organism cannot be seen or found doesn t mean that such an organism isn t present and causing disease. To monitor orchard for diseases, disease symptoms should be known and responded to. The monitoring procedures and protocols for diseases are very similar to that of pests. The only major difference is that one often has to take samples in the orchard and send it away to a laboratory for identification, rather than simply noticing and counting a number of insects. Remember that the appearance of some pests and insects may also be an indicator that disease is about to occur, or has already infected your orchard. In conjunction with the CRI, Diagnostic Centre (DC) in Nelspruit, specific analyses can be done to detect diseases. Here follows a list of techniques used to determine if diseases are present in the orchard: leaf bating technique is used to isolate Phytopthora. This attracts fungal zoospores by plant exudates to the leaf discs. This method can also be used to isolate Pythium. Different cultures are used to grow these organisms and thus determine the presence of either disease in the Diagnostic Centre. The DC has also altered the leaf disc baiting technique to test irrigation water for the presence of Phytophthora and Pythium. Fruit samples can be submitted to the DC to have them isolate above-ground fungi leaving lesions on the fruit. The DC can assist in nematode root counts. A detailed description of making and placing a Spore Trap to analyse irrigation water is described in the CRI Integrated Production Guidelines Volume III p

27 All samples submitted to the DC should be done as per their guidelines and must be accompanied by filled in analysis forms obtainable from the DC. The DC releases the results of any samples submitted within approximately 10 days. The CRI, Diagnostic Centre contact details Laura Huisman P O Box 28 NELSPRUIT 1200 Telephone No Fax No Or visit 3. Diseases and Symptoms Table 3.1 defines a list of the most commonly occurring and economically damaging pests in citrus orchards. List of Diseases Fruit or Foliar Soil borne Graft transmittable Alternaria Navel-end rot Nematode Tristeza Botrytis Root rot Greening Phaeoramularia Armillaria Root Rot Diplodia Phytophthora Brown rot black spot Table 3.1 List of Diseases The specific symptoms of these diseases were discussed in detail in the level 2 guide. Please revise them in order to train yourself in the requirements of monitoring and identifying these diseases by revising this carefully. 4. Disease Prevention in To minimise the occurance of diseases, the following rules should be adhered to: Only purchase plant material from certified and approved nurseries that have declared the plants disease free. Prevent the movement of plant material between production areas, especially if a known disease is found in one area and not the other. Before a new orchard is established, remove all traces of former plant material from the soil before planting and have the soil analysed for the presence of disease causing organisms. Nematicides can often be used to treat the soil before the new trees are planted and to prevent new plants from contracting diseases. Never bring fruit and plant material into the country on your own without declaring and clearing it through import control. Diseases easily spread from one country to the next in this way. Be alert to abnormal growth and unusual occurrences in the orchards and consult experts to identify the source. 27