How can we make Biological Control more economical?

Transcription

1 How can we make Biological Control more economical? Economy of Chemical Control Synthetic Pesticides = Responsive Control Preventative control is difficult Not a problem if pesticides are effective Potential for crop loss when resistance occurs Risk management considerations Pesticide resistance difficult to predict All or nothing scenario Without resistance, cheap and secure, but In case of multiple resistance, no option but to switch to other control methods Economy of Biological Control Biological Control = Preventative Control Responsive control difficult and very expensive Risk management considerations If control fails, crop may be rescued with pesticides (resistance difficult to predict) How much time do we have to correct failures? The shorter the crop cycle, the higher the insurance cost necessary for overkill How severe is the damage to the control system if we have to use pesticide (other crops / pests)? Economy of Biological Control Economy a question of crop insurance: How much premium should we pay? No economic damage threshold in Ornamentals Not enough time to assess what works If control fails do we know what did not work? Quality price ratio of beneficials? Difficult to assess quality of beneficials How to assess intangible benefits such as Marketing advantages? Improved morale of greenhouse staff? 1

2 No Economic Damage Threshold Economy of Biological Control How do we make Biocontrol more economical? without damage thresholds for economic control we can only try to avoid waste learn about the limits of each control system avoid stretching these limits don t t skimp on preventative costs don't skimp on detailed application labor purchase inexpensive beneficials when possible purchase expensive beneficials when necessary take the early loss - spray when really needed Cost Comparison Chemical vs Biological Control Whitefly Control Poinsettias 2005 at Jeffery's Pesticides 2004 Biologicals 2005 Cost per pot $ $ Cost per cutting $ Total numbers of Biological Control Agents released for each 1000 pots that were produced: E. mundus 2,000 E. eremicus 650 Eretmocerus mix 50 Encarsia formosa 1,100 Amblyseius cuc. 20,000 Cost Comparison Chemical vs Biological Control Eretmocerus eremicus 11% Encarsia Formosa 7% Eretmocerus mix 1% Eretmocerus mundus 45% Biological Control Poinsettia 2005 Distribution of Cost Nemasys F 18% Amblyseius cucumeris 7% Total Aphid Control 7% Total Mite & Fungus Gnat Control 4% Nemasys F total of 1 tray of 250 million for every 4000 pots 2

3 Example: Spider Mite Control Two Spotted Mites on Rose Two Spotted Spidermite Example: Spider Mite Control What are the tools that we use? Phytoseiulus persimilis Amblyseius californicus Amblyseius fallacis Amblyseius andersonii Soft pesticides such as Floramite, Shuttle, and Vendex Lewis Mite Damage on Poinsettia Photos courtesy of Graeme Murphy and Gillian Ferguson (spider mite) Example: Spider Mite Control Limitations of Phytoseiulus persimilis: Needs spider mite to survive not ideal for preventative programs Narrow temperature range not very effective below 18 C not very effective above 28 C Economic use as biological pesticide only in the right temperature range for pockets of spider mite infestations Example: Spider Mite Control Phytoseiulus is useful as a biological pesticide 3

4 Example: Spider Mite Control Limitations of Amblyseius californicus: Much less effective at cleaning up than Phytoseiulus persimilis Do not use once outbreaks are detected BUT Much more heat tolerant than P. persimilis Survives in absence of Spider Mites Will also feed on Broad Mite / Cycl. Mite Cost effective predator in preventative programs at low introduction rates Amblyseius californicus Under the microscope: This is a piece of bran as it ships from your supplier Fast moving pear-shaped mites are the predators The slow moving mites with long hairs are feeder mites Usually much more feeder mites than predators If it runs fast, it s s a predator If it moves slow, it s s food Example: Spider Mite Control Limitations of Amblyseius fallacis: Not effective at cleaning up infestations Reproductive Diapause in SD and Cold Temp. Less heat tolerant than A. californicus BUT Adults still active and feeding in winter Provides some mite control at < 15 C Will also feed on Broad Mite / Cycl. Mite Cost effective preventative predator for cool crops before mites are detected Cyclamen and Broad Mite 4

5 Example: Cyclamen and Broad Mite What are the tools? Amblyseius fallacis Amblyseius californicus Amblyseius andersonii Amblyseius barkeri Same limitations as for Spider Mite Control All biocontrol of these mites must be Preventative Timing of release programs is critical Learn about pest and beneficial!!! Example: Cyclamen and Broad Mite Challenges with soft mite control: None of the control tools work very fast Crop damage visible before pest detected High risk of crop loss/damage curative biocontrol does not prevent crop loss curative biocontrol usually not economical Prevention is key: apply biological controls when conditions for mites are less than optimal apply chemicals when infestations detected Example: Cyclamen and Broad Mite Upper Temperature Threshold for Pest: Cyclamen Mite about 27 C Broad Mite about 30 C For fall crops apply controls in summer (populations are dormant) For spring and summer crops: apply controls to susceptible crops bi-weekly from the start before mites are detected use indicator plants for early detection spot-spray spray immediately where crop damage Indicator Crops for Broad Mites Our indicator crops are: Hedera, Thunbergia, Vinca We scout these crops regularly and in detail (microscope) for presence of broad mites Even with no pest presence we apply preventative predatory mites regularly If we find broad mites on these crops, we begin to treat other plants that are known hosts 5

6 Example: Cyclamen and Broad Mite Why not Amblyseius cucumeris? A. cucumeris DOES feed on Cyc. & Broad Mite But in our experience no effective control Cyclamen and Broad Mite best controlled outside their temperature optimum At temperature optimum the pest outperforms all beneficials Temperature optimum for A. cucumeris is the same as for the Pest A. cucumeris not suitable in short term crops because it works best at the wrong time of year? Example: Thrips Control Example: Thrips Control Aspects determining the economy and cost of biological thrips control: Temperature (Weather / Season) Which predator best suited? Crop: Which crop is the preferred thrips host? Which predator avoids which crop? Pest ID : Which Thrips are you trying to control? Example: Thrips Control - Temperature Temperature limitations of thrip predators: Amblyseius cucumeris upper threshold for survival approx. 33 C Amblyseius swirskii most effective at temps > 25 C more heat tolerant than A. cucumeris in ornamentals not more effective than A. cuc A. montdoriensis future option at high temp? Orius insidiosus only in LD and >22 C 6

7 Example: Thrips Control - Temperature Example: Thrips Control - Temperature My strategy: in winter Amblyseius cucumeris because it is cheap Amblyseius swirskii not cost effective for us Nematodes incl. S. carpocapsae (frequency?) in summer check long-term forecast >30 C C daytime high (outdoors) begin mixing 50/50 A. cucumeris and A. swirskii >35 C C daytime high only A. swirskii increase frequency of Nematode applications Example: Thrips Control - Crops Which crops are attractive to thrips (green)? examples: Dahlia, Double Impatiens, Ipomoea Strategy: Load these crops with much higher rates of predatory mites than other species Choose these crops for pest monitoring Allow for somewhat higher thrips thresholds on these crops before disrupting biocontrol Example: Thrips Control - Crops Which flowering crops are problematic? examples: Gerbera, Cyclamen, Pot Mums Strategy: Use alternate controls such as Orius on flowers with suitable structure and pollen (Gerbera) Consider Mini Sachets at 1 per pot Biocontrol systems are (thus far) not suitable to finish all crops (Cyclamen) - need insecticides Check flowers for thrip before applying spray Consider the benefits of repellent side effects of certain pesticides 7

8 Thrips Control Alternative Strategies Mass Trapping with Yellow Sticky Tape is very effective when biocontrol relies primarily on predatory mites Example: Thrips Control - Crops Which crops are unsuitable for standard beneficial programs? examples: Ipomoea, Portulaca, Dracaena Strategy for these crops: don t t waste money on cheaper standard beneficials if you know that they just wont work use alternate strategies on select crops, even if they are nominally more expensive e.g. Orius + supplement food on Ipomoea e.g. Hypoaspis aculeifer on Dracaena Example: Thrips Control - Pest ID Can you tell which thrips species is on your card? Example: Thrips Control - Pest ID Amblyseius cucumeris will not effectively control Thrips species larger than WFT Nematodes will only control Thrips, which pupate in the soil Some secondary Thrips can increase card counts without doing crop damage Learn how to identify the pest buy a good stereo microscope learn about the different species of pests Ceranisus species 8

9 Do Your Bios Arrive Alive? Make it a habit to check the quality of every shipment before and after distribution Do Your Bios Arrive Alive? How can you tell? Check shipments of mites under microscope Get a a feel for what it should look like days after release check your cards of whitefly parasitoids for ratio of emergence Check mummies of Aphid parasitoids for emergence Check empty Aphidius mummies for signs of hyperparasitism (jagged edges on exit hole) In mid-summer and in mid-winter check the temperature of each shipment upon arrival Example: Thrips Application Methods Amblyseius cucumeris: Uniform distribution Load known thrips hosts Use suitable product form Nematodes: Start early (propagation) Mix w. Botanigard on rooting bench? Met-52 will be registered - Option for mix? Application Frequency Needs free water Example: Thrips Product Form Product form for Amblyseius: Mini sachets for high pest pressure Minis are cost effective when failed thrips control would jeopardize the success of high value crops Standard slow release when climate is suitable and mites can distribute across topography A. cucumeris is not very mobile match product form to climate/container absolutely critical at higher temp / low r.h. 9

10 Example: Thrips Product Form We always supplement bulk mites on floor or benches, when we use slow release sachets Example: Thrips - Details are Important!!!! With Amblyseius cucumeris: begin to treat early before pest pressure builds recognize lag time in pest monitoring results avoid untreated pockets supplement slow release product with bulk mites to avoid safe haven pockets for thrips increase distribution rates on preferred host crops check long-term weather forecast: Supplement other WFT controls (Orius, A. swirskii) when temperatures exceed 30 C C / 85 F Uniform Distribution is Critical Example: Thrips - Details are Important!!!! A. cucumeris - Details we should know: feeds only on early instars of WFT does not control other stages of WFT does not control larger Thrip species likes high r.h - seeks moist microclimate in crop suffers in high temperatures >33 C C / 90 F is not very mobile, especially in dry environment presence in crop is difficult to monitor 10

11 Example: Thrips - Details are Important!!!! Why do we need to know lifecycles? Example A. cucumeris release rates It takes minimum of weeks from deciding on action to visible effect on sticky cards we count only adults on sticky card sticky cards read insect count with delay (1 wk) 1 wk from order to delivery of bio-controls 2-33 weeks until oldest controlled thrip stage becomes adult (bios won t t eat older thrip) min. 1 wk before any reduction in hatching adults shows up as reduction of sticky card count Questions? Albert Grimm Jeffery s s Greenhouses Inc. AlbertG@jefferysgreenhouses.com 11