improved (2, 3, 4, 5, 7, 8, 9, 10, 11). Some of the

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1 8 FLORIDA STATE HORTICULTURAL SOCIETY, 963 EVALUATING SPRAY EQUIPMENT FOR FLORIDA CITRUS R. F. Brooks, W. L. Thompson nd P. T. Jutrs Florid Citrus Experiment Sttion Lke Alfred The first successful, lrge, ir-blst, dilute spryer ws introduced to Florid citrus in 937. Since then, spry equipment nd methods of p pliction hve been periodiclly evluted nd improved (, 3, 4, 5, 7, 8, 9, 0, ). Some of the improvements hve included incresed ir horse power, ir directing ttchments, nd new types of spryers s well. Current investigtions hve emphsized the evlution of spry equipment on the bsis of spry distribution s well s control of insects nd mites. Methods nd Mterils Tretments in ech of the experiments re ported here were methods of ppliction or mkes of spryers. Ech spryer pplied the sme mount of pesticide per cre in ech experiment, but the volume of wter ws vried s required. Tretments were rrnged in rndomized block design with four replictes. Plot size vried from 6 to 0 rows wide by 0 to 4 trees long. Count or smple trees were selected from the center two rows of ech plot with t lest two buffer trees t ech end of the row. Coverge rtings were estblished with modifiction of the method reported by Edwrds et l. (). This method involves sprying with fluorescent mteril, (Sylvni Phosphor 8) nd then observing the distribution of this m teril on smple leves with the id of drk cbinet equipped with n ultrviolet (537.u.) lmp. The rting system ws modified to () (poor) to 5 (excellent) insted of to 3. Sm ples of 50 leves from the inside top nd from the skirt of ech tree were compred with set of stndrds prepred in the lbortory. Ech lef ws rted on both surfces by t lest two observers. Citrus rust mite popultions were mesured before nd t intervls fter tretment by de termining the percentge of leves nd fruit in fested in smples of 5 leves nd 5 fruit per tree. This procedure ws lso crried out in tree Florid Agriculturl Experiment Sttions Journl Series No lformerly t the Florid Citrus Experiment Sttion, now Privte Consultnt. Lke Alfred. tops whenever possible. Scle popultions were determined by count of the numbers of third stge femle scle on 50 leves picked t rndom from round the skirt nd from the inside top of ech tree. Results nd Discussion Helicopter Experiments, Thompson et l. () reported tht helicopter trveling t ground speed of 5 mph produced better cover ge when flown between the rows thn when flown over the tree tops. In spite of this im provement, spry coverge with helicopter hs been poor when compred with conventionl ir-blst spryers. This is well illustrted by the dt presented in Tble. These dt re summry of the results of six experiments nd show significntly better coverge with n irblst spryer thn with helicopter. Although spry coverge ws poor with helicopter s compred with n ir-blst spryer, no significnt difference in rust mite control ws found in six of seven experiments. The dt presented in Tble re the results of one experi ment, but re typicl of ll six. In ech of these six tests, chlorobenzilte ws used t the rte of 3 pints per cre in either 5 or 0 gllons of wter. In the one experiment in which the helicopter filed to control rust mites, only two pints of chlorobenzilte were pplied per cre. The p plictions in this experiment were mde on July, 96, when 6 per cent of the fruit ws in fested. Two weeks lter the helicopter spryed plots hd to be respryed becuse 49 per cent of the fruit ws infested. In contrst, the ir-blst spryer effectively controlled the mites for eight weeks. Only few experiments hve compred heli copter nd n ir-blst spryer in the ppliction of sclicides becuse scle popultions in most groves hve been t such low levels tht sig nificnt differences could not be detected even between treted nd untreted plots. However, enough Glover's scle ws found in one experi ment. The dt from this experiment re pre sented in Tble 3 nd show tht control of Glover's scle nd spry coverge closely prllel ech other. These dt further show tht there ws n increse of scle in plots spryed with the helicopter, but decrese in those spryed with conventionl ir-blst spryer (Speed

2 BROOKS, THOMPSON, JUTRAS: SPRAY EQUIPMENT 9 Tble. Spry coverge obtined with helicopter nd n ir-blst spryer on Florid citrus. Grove -- Loction s -- Height Helicopter 9 Coverge Rtings ' with: Air-Blst4 -- Lke Alfred Grpefruit -- 8f-5!.98 b Lucerne Prk Grpefruit -- 8t-0I.5 b Agricol Ornge -- 5!-8!.5 b Lke Wles Ornge -- f-5!.35 b Bbson Prk Ornge -- 8f-f.5 b Minneol Ornge --!-5!.38 b.96 Coverge Rtings: 4 = very good, nd 5 poor, = fir,.5 excellent. stisfctory, 3 = good, Results of Duncn's Test: Tretment mens followed by different letters re considered different t the per cent level. ^Groves t Lke Alfred, Lucerne Prk nd Agricol were spryed with n Alouette helicopter while groves t Lke Wles, Bbson Prk nd Minneol were spryed with Bell helicopter. Air-blst spryer equipped with 4" fn nd double oscillting volute. Spryer, 703). The scle popultion incresed t similr rtes in helicopter plots nd plots re ceiving no sclicide. Air Blst Spryer Experiments Evlu tion. Air-blst spryers were evluted on the bsis of coverge nd pest control. Although no significnt differences in control of citrus mite ws found between ny of the spryers listed in Tbles 3 nd 4, these spryers did differ in de gree of coverge nd mount of scle control in tree tops. There ws no significnt difference in scle control on the tree skirts lthough there were some differences in coverge rtings in one experiment s shown in Tble 4. Scle control nd coverge were closely cor relted in the tops of mture citrus trees. Using the results obtined in the tree tops s the bsis of evlution, the dt presented Tble 3 nd 4 show tht: () the Speed Spryer 903 ws effec tive both s dilute nd concentrte (6X, % gl.) spryer, () the 700 Model S.S. ws effective s dilute spryer but only fir s concentrte spryer (6X, Ys gl.), (3) the Myers spryer ws n effective concentrte (6X, % gl.) but poor dilute spryer, (4) the R.S.M. spryer ws effective t 0X nd mph but not t 0X nd mph, nd (5) the Mrlow Economist while performing stisfctory on skirts ws poor in the tree tops. Concentrting with Speed Spryer 90S. One experiment determined the concentrtion of spry mterils tht could be used in the lrger 903 Speed Spryer nd still mintin good cover ge. This experiment ws conducted in grove of mture grpefruit trees tht were 5 to 30 feet high, hedged, nd thickly folited.

3 0 FLORIDA STATE HORTICULTURAL SOCIETY, 963 Tble. Rust mite control with chlorobenzilte pplied by helicopter nd by ir-blst spryer. Minneol, Florid. 96. Per Cent Rust Mite Infested--Dys fter Sprying Tretments 4 Leves Fruit Speed Spryer Bell Helicopter Untreted Check 4.0 b b 4.8 b 7.7 b 7.6 b 4.0 b 60.3 b Tretments pplied August, 96 nd consisted of 3 pints of prthion 4E nd 3 pints 5 per cent liquid chlorobenzilte per cre. Results of Duncn's Test: Tretment mens followed by the sme letter re not considered different t the per cent level. Tble 3. Evlution of different types of spryers using prthion for the control of Glover's scle. Bbson Prk, Florid. 96.l Tretment Coverge^ Rtine Glover's Scle per Lef Pre-Spry Post Sprv4 Coverge Rtine Glover's Set Post S Tmf Speed Spryer Speed Spryer R.S.M. Concentrte (0X) Side b Myers A4 (No Oscilltion) b b Mr low Economist (33X) Side c b Bell Helicopter. b b. c c No Sclicide c d Prthion used t the rte of 4.5 lb. ctul per cre, chlorobenzilte t the rte of.5 lbs. per cre. Sprys were pplied on April 9-, 96 t ground speed of mph with the exception of helicopter which trveled t pproximtely 5 mph. Vlenci ornge trees 8- feet high. Coverge Rting System: «poor, = fir,.5 = stisfctory, 3 = good, 4 = very good, nd 5 = excellent. 4Pre-spry counts mde on Mrch 8, 96. Post spry counts mde on June 7, 96. Results of Duncn's Test; All tretments followed by the sme letter re not considered different t the 5 per cent level.

4 BROOKS, THOMPSON, JUTRAS: SPRAY EQUIPMENT Tble 4. Evlution of concentrte spryers for scle insect control. Bbson Prk, Florid. 963., Leves From: Ground Speed Coverge^" Rtine Scle5 Per Lef Coverge^" Rting Scle5 Per Lef Myers A4 Modified3 6X, /8 gllonge mph Speed Spryer 903 6X, /8 gllonge mph Speed Spryer 704 6X, /8 gllonge mph.79 b b 0.47 b Dnish R.S.M. Side 0X mph.9 b c 0.80 be Mrlow Economist 33X.5 mph.6 b d.9 c Side Spryers pplied 4.5 lbs. ctul prthion nd.5 ctul chlorobenzilte per cre. Applictions mde April -6, 963 to Vlenci ornge trees 8- feet high. 30scilltors removed. Coverge Rting System: = poor, = fir,.5 = stisfctory, 3 = good, 4 = very good, nd 5 = excellent. 5Totl of purple, long, chff nd Florid red scle. Pre-tretment counts rnged from.39 to.64 per lef. 6Results of Duncn's Test: Tretment mens followed by the sme letter re not considered different t the 5 per cent level. The results of this experiment re shown in Tble 5. These dt revel tht stisfctory coverge on the skirt ws reched t 0.5X or Gllons Tble 5. Spry coverge t vrious concentrtions with 903 Speed Spryer. Lke Alfred, Florid. 96. Ground Speed (mph) ' Concentrtion (X) 58.OX 37.3X 3.X 9.OX 8.6X 3.7X 0.5X 0.OX 8.3X 7.4X 6.5X Coveree Rting <.00 c.00 c.06 c.07 c.39 c.6 be.6 be.6 be.06 b.8.93 >n Leves from Skirt.00 c.00 c.06 c.09 c.54 c.3 b.63 b Coverge Rting system: i - poor,» fir,.5 - stisfctory, 3 - good. 4 =»er, good. ^ 5 - excellent. lower while 7.4X or lower ws needed in the tree tops. Therefore, the recommended 6X, % gllonge not only pplies to previous models of high volume ir-blst spryers, but lso to the 900 series Speed Spryer s well. Pump Pressure. The effect of pump pressure upon the effectiveness of n ir-blst spryer lso ws studied. A Speed Spryer 703 ws fitted with high pressure pump insted of the stnd rd low pressure centrifugl pump nd sprys were pplied t different pressure settings. The nozzle sizes were chnged t ech setting so tht the sme volume of spry ws pplied t ech pressure. The results of this experiment re shown in Tble 6. These dt show tht there ws no significnt difference in coverge between pres sures of 00 to 400 lb./in., but tht these higher pressures were significntly better thn the lower pressures. Although incresed pump pressure improved spry coverge with the Model 703 Speed Spryer, it cnnot be ssumed tht in cresed pressure would improve coverge with j mkes nd models of spryers. Ech spryer ^ ^^ fo ^ individully evluted. 3n.tt. hedged grpefruit tree feet high. Oscilltion. A question often sked is, "How importnt re oscilltors to spry coverge?"

5 FLORIDA STATE HORTICULTURAL SOCIETY, 963 Tble 6. Effect of high pressure on coverge with n ir-blst spryer. Lke Alfred, Pump Pressure (lbs./in.) Florid (S tndrd. Centrif.) (High Pressure)4 H.. II,. It Coverge Rting of Leves from J.4 b.3 b-.46 b b.30 c.55 b Coverge Rting System: = poor, = fir, /5 = stis fctory, 3 = good, 4 = very good, nd 5 = excellent. ^Results of Duncn's Test: Tretment mens followed by the sme letters re not considered different t the per cent level. 3Speed Spryer Model 70 with centrifugl pump. Speed Spryer Model 703 with 60 gpm pis ton-type high pressure pump. This question ws prtilly nswered by n ex periment with Speed Spryer 903 nozzled for dilute sprying nd with oscilltors connected s well s disconnected. The results of this experi ment re shown in Tble 7 nd revel tht there ws significntly better coverge with oscilltion. While these dt revel the importnce of oscil ltion to the performnce of the 900 series Speed Spryer, ech mke of spryer will hve to be evluted on the merits of its own sprying sys tem. Tretment Tble 7. Effect of oscilltion upon spry coverge with 903 Speed Spryer nozzled for dilute sprys. Lke Alfred, Florid. 96. Coverge Rting on Lef Surfces on Leves from Skirt I*wer Oscilltion.78 Z No Oscilltion.80 b.08 b b Coverge Rting System: - poor, = fir,.5 "stis fctory, 3 = good, 4 = very good, nd 5 = excellent. Results of Duncn's Test: Tretment mens followed by the sme letter re not considered different t the per cent level. Summry Helicopters provided poor coverge nd poor control of Glover's scle, but were stisfctory for the control of citrus rust mite when chlorobenzilte ws pplied t the rte of three pints per cre. Scle insect control nd degree of coverge closely prlleled ech other with helicopters s well s the ir-blst spryers tested. The only differences between ir-blst spryers ws in how effectively they spryed tree tops. Effective spryers were the Speed Spryer 903, both di lute nd concentrte; Speed Spryer 700, dilute only; Myers A4, modified concentrte; nd the R.S.M. t 0X concentrtion. The Mrlow econ omist produced poor coverge nd poor control of Glover's scle in tree tops, but like ll ir-blst spryers, produced good control of citrus rust mite. The new model 903 Speed Spryer s con centrte spryer ws found to perform best t 6X nd Vs dilute gllons. It ws lso found tht high pump pressures improved coverge with 703 Speed Spryer nd tht oscilltors ^were vety importnt in the performnce of model 903 dilute spryer. LITERATURE CITED. Edwrds, G. J., W. L. Thompson, J. R. King nd P. J. Jutrs. 96. Opticl determintion of spry coverge. Trns, of A.S.A.E. 4: Griffiths, J. T., C. R. Stems nd W. L. Thompson Possibilities for the use of concentrted sprys on citrus in Florid. Proc. Fl. Stte Hort. Soc. 63: , C. R. Stems nd W. L. Thompson. 95. Comprison of dusting nd sprying over 3 yer period. Citrus Mgzine 5() : King, J. R. nd J. T. Griffiths Results of the use of concentrte spryers in citrus groves in Florid. Fl. Entomol. 3: , W. L. Thompson nd W. T. Khl Improved mchinery for citrus production. Fl. Agr. Exp. St. Ann. Rept , P. J. Jutrs nd W. L. Thompson Current studies on the efficiency of equipment for the p- pliction of pesticides to citrus trees in Florid. Proc. Fl. Stte Hort. Soc. 7: Stems, C. R., W. L. Thompson nd J. T. Griffiths Effects of methods of ppliction on copper, sulfur, nd oil deposits obtined by sprying nd dusting. Proc. Fl. Stte Hort. Soc. 6: ,J. T. Griffiths, W. L. Thompson nd E. J. Deszyck. 95. Progress report on concentrted sprys on citrus in Florid. Proc. Fl. Stte Hort. Soc. 64: , W. L. Thompson, R. B. Johnson nd E. J. Deszyck. 95. Methods of pplying insecticides with different spry mchines. Proc. Fl. Stte Hort. Soc. 65: Performnce of the volute t tchment for the Speed Spryer. Citrus Industry 33(6): 8.. Thompson, W. L Results of different methods fo oil ppliction for the control of scle insects on citrus. Proc. Fl. Stte Hort. Soc. 5: , P. J. Jutrs, M. Cohen nd "R. F. Brooks. 96. Efficiency of equipment for the ppliction of pesticides to citrus trees. Fl. Agr. Exp. St. Ann. Rept