ON WATERMELON IN SOUTH FLORIDA

Transcription

1 76 FLORIDA STATE HORTICULTURAL SOCIETY, 96 INSECTICIDAL CONTROL OF LEAF MINER ON WATERMELON IN SOUTH FLORIDA Associte W. C. Adlerz Entomologist, Wtermelon nd Grpe Investigtions Lortory Leesurg Astrct Tests of chemicls to control the lef miner Liriomyz trifolii (Burgess on wtermelon were conducted from 962 to 967 t Immoklee, Florid. Control with dimethote (Cygon ) nd zinphosmethyl (Guthion ) ws consistently good nd these chemicls hve een recom mended to growers. Other excellent folir spry mterils were SD 3562 (Bidrin ) nd SD 929 (Azodrin ). Ten other mterils tested s folir sprys were not effective. Control ws effective for t lest 6 dys fter nded preplnt soil tretment with UC 29 (Temik ). Stnd ws reduced when seeds were plnted in the grnule nd, ut not when they were plnted 2 inches from the nd. Four other mterils were ineffective when used in the sme wy s UC 29. Introduction The lef miner Liriomyz trifolii (Burgess) () is one of the mjor pests of wtermelon in south Florid. It hs een prolem ech yer since the lst mjor outrek in 96. Routine insecticide pplictions to smll plnts hve een necessry in south Florid ech yer, ut they hve never een required in centrl or north Florid. Experiments on chemicl control of this in sect hve een previously descried (). Evlu tions of chemicls tht led to present recom mendtions nd evlutions of cndidte insec ticides for future recommendtions re presented in this pper. Mterils nd Methods Chrleston Gry wtermelon plntings were mde t the South Florid Field Lortory t Florid Agriculturl Experiment Sttions Journl Series No. 32. Immoklee in Decemer (Jnury in 966) nd tretments were pplied in Jnury nd Feru ry. Ech experiment consisted of 3 replictes of 9 or 2 tretments in - or -hill plots. Folir sprys were pplied with -gllon pck spryers, the systemic insecticides weekly or iweekly nd the non-systemic insecticides weekly or twice weekly. Sprys were pplied t rtes vrying from 3 gllons per cre on smll plnts to 5 gllons per cre on lrge ones. Seeds were plnted in hills 3 feet prt in continuous furrow long the middle of the plnt ed. Grnulr formultions of systemic insecticides were pplied in continuous nd in the seed furrow. Since toxicity to seeds might e fctor, seeds were lso plnted in furrow 2 inches to one side of the treted furrow in 967. Phytotoxicity ws lter evlu ted y plnt stnd. Topicl pplictions of grnules were mde in continuous nd down the middle of the ed nd over the top of the young plnts. Tretments were evluted y rering insects from leves per plot from the most infested leves ner the crown of the plnts. The lef smples were tken dys fter iweekly folir pplictions of insecticides, 3 dys fter weekly pplictions. Results experiments. These experiments included folir sprys nd preliminry work with grnulr systemics. Only 3 of cndidte insecticides tested were consistently effective (Tle ). Dimethote (Cygon ), systemic insecticide, ws consistently the most effective mteril in controlling lef miners when pplied weekly in ll tests from, 962 to 965. Weekly nd iweekly pplictions were compred in 96, ut the infesttion ws so light tht there ws complete control fter oth tretments in dicting tht iweekly sprys re dequte when there re few lef miners. Hrris (6) reched similr conclusions with lef miner (proly L. trifolii) on celery. Azinphosmethyl (Guthion ), non-systemic insecticide, ws sttisticlly comprle in ef fectiveness with dimethote whether pplied

2 ADLERZ: WATERMELON LEAF MINER CONTROL 77 weekly or twice weekly in tests from 962 to 965 (Tle ). Control of hevy infesttion ws good with twice-weekly sprys in 963. Adlerz () previously reported tht zinphosmethyl pplied twice weekly kept lef miners elow per lef in hevy infesttion. Azinphosmethyl ws the only non-systemic in secticide tht Hrris (6) considered effective when pplied s infrequently s once weekly. SD 3562 (Bidrin ), systemic insecticide, ws sttisticlly comprle in lef miner con trol with dimethote in ll tests from 962 to 965 (Tle ). Control of hevy infesttion in 963 ws intermedite etween tht of di methote nd twice weekly zinphosmethyl, ut there ws no sttisticl difference mong the 3 mterils. The infesttion ws so low in 96 tht oth weekly nd iweekly pplictions of SD 3562 gve complete control experiments. These experiments included systemic insecticides only, nd emph sized the use of grnulr formultions in the Tle. Numer of insects surviving in 3-lef smples of wter melon following insecticide tretments. Immoklee, Florid, Tretment* AI/** or AI/A 962 Numer pupe 963 of rered ** Dimethote E Dimethote 267E Dimethote E iweekly Azinphosmethyl 2E 2 weekly Azinphosmethyl 2E SD E SD E SD E iweekly Ni 22 5W Ni 22 5W UC 27A 2E UC 27A 2E GS 35 E GS 35 E Phosphmidon E Phosphmidon E iweekly Ethion E 2 weekly Phorte G preplnt & topicl Phorte G topicl Phorte G preplnt Disulfoton G R 5 3E 2 weekly GC 377 E 2 weekly Nled E 2 weekly Dizinin 25W +Prthion 5W 2 weekly Untreted O e 27 c 2 e 326 c 275 e l I c ll XXX Tretments pplied weekly unless otherwise specified. Ounces of ctive ingredient per gllons or per cre in the cse of grnules (G). Vlues followed y the sme letter re not significntly different t the 5 percent level ccording to DuncnTs multiple rnge test.

3 7 FLORIDA STATE HORTICULTURAL SOCIETY, 96 Tle 2... Numer of lef miners surviving in 3-lef smples of wtermelon following insecticide tretments. Immoklee, Florid,. 966 Tretment* AI/** or AI/A Numer of pupe rered 3//66 3/3/66" Men*** UC 29 G UC 29,G SD WS Dimethote 267E UC 29 G Azinphosmethyl 2E Ni 22 G UC 27A 5W Untreted { Ni 22 G Ni 22 G UC 27A 5W l All folir pplictions weekly in this test. Ounces of ctive ingredient per gllons or per cre in the cse of grnules (G). Vlues followed y the sme letter re not significntly different t the 5 percent level ccording to DuncnTs multiple rnge test. soil. Lef miner control with folir-pplied SD 929 (Azodrin ) ws excellent in 966 nd 967 (Tle 2 nd 3). In 967 the infesttion ws hevy nd control with SD 929 t ounces ws sttisticlly comprle with tht of dimethote t ounces. UC 29 (Temik ) ws very effective for 6 dys following soil ppliction in 966. In 967, even the -ounce rte of UC 29 effec tively controlled hevy infesttion for 67 dys nd the degree of control ws sttisticlly com prle to tht with dimethote. In oth yers the infesttions disppered efore the limits of effectiveness of the mteril could e determined. Seedlings were dmged nd stnd ws re duced when seeds were plnted in direct con tct with UC 29 grnules (Tle ). When seeds were plnted 2 inches to the side of the grnule nd, plnts were not injured or sig nificntly reduced in numer. Brnowski () encountered the sme kind of prolem with grn ulr systemic insecticides pplied to tomto seeds nd solved the prolem in the sme wy. UC 29 ws the only grnulr systemic mteril tht effectively controlled lef miner on wtermelon when pplied to the soil efore plnting. Phorte (Thimet ) nd disulfoton (Di Syston ) were not effective. Other ineffective grnulr systemic insecti cides were By 25 (Terrcur -P ) nd Ni 22 (Furdn ). Ni 22 did not dmge seedlings in the grnulr insecticidl phtotoxicity test (Tle ). UC 27 A ws the only other insecticide tested s folir spry in 966 nd it ws not effective. Discussion Of cndidte insecticides tested ginst wtermelon lef miner from 962 to 965, only 3 were consistently effective. Two of these, di methote nd SD 3562 re systemic nd one, zinphosmethyl, is not. Phorte nd disulfoton pplied s grnulr systemics in the soil were completely ineffective, lthough oth hve een shown to e effective ginst lef miners on other Florid crops (2, 3,,5,7). The 2 new systemic mterils tested in 966 nd 967, SD 929 (folir ppliction) nd UC

4 ADLERZ: WATERMELON LEAF MINER CONTROL 79 Tle 3. 'Numer of lef miners surviving in 3-lef smples of wtermelon following insecticide tretments. Immoklee, Florid, Ferury, 967 _^ Tretment* AI/** or Numer of. AI/A pupe rered SD WS Dimethote 267E SD WS UC 29 G UC 29 G UC 29 G By 25 G By 25 G Phorte G By 25 G Disulfoton G Untreted All Folir pplictions weekly in this test. Ounces of ctive ingredient per gllons or per cre in the cse of grnules (G). Vlues followed y the sme letter re not significntly different t the 5 percent level ccording to Duncn!s multiple rnge test. 29 (soil ppliction), controlled lef miners rindworm control progrm. Investigtions re effectively nd cn e recommended for use on eing continued on the ltter point. wtermelon when they re mde ville for this purpose. However, single ppliction of Acknowledgment UC 29 my eliminte the need for folir The coopertion of Dr. Pul H. Everett of sprys of insecticides prior to inititing the the Florid Agriculturl Experiment Sttion's Tle. Stnd of cotyledon-sized plnts 9 dys fter plnting in contct with nd 2.inches to one side of insecticide. grnules. Immoklee, Florid, 967 Tretment AI/A Numer of plnts % chnge 2" to side In grnules in grnule; Ni 22 G ** +3 Ni 22 G ? Ni 22 G UC 29 G UC 29 G c -37 UC 29 G 6 2 d -6 Jfc ## Ounces of ctive ingredient per cre. Vlues followed y the sme letter re not significntly different t the 5 percent level ccording to Duncn's multiple rnge test. Numer of plnts emerged from seeds.

5 FLORIDA STATE HORTICULTURAL SOCIETY, 96 South Florid Field Lortory, Immoklee, Florid, in conducting ll tests descried herein is grtefully cknowledged. LITERATURE CITED. Adlerz, W. C. 96. Control of lef miner on wter melon in centrl nd south Florid. Proc. Fl. Stte Hort. Soc. 7: Brnowski, R. M Preliminry work with sys temic insecticides on tomtoes. Proc. Fl. Stte Hort. Soc. 72: Brnowski, R. M. 96. A report on the use of systemic insecticides on some vegetle crops. Proc. Fl. Stte Hort. Soc. 73: 6-.. Brnowski, R. M Effectiveness of vrious methods of pplying systemic insecticides to tomtoes. Proc. Fl. Stte Hort. Soc. 75: Genung, Willim G. nd Emmett D. Hrris Jr. 96. Notes on the iology nd control of serpentine lef miner in the Evergldes. Proc. Fl. Stte Hort. Soc. 7: Hrris, Emmett D. Jr., 962. Insecticides nd inter vls etween ppliction for lef miner control on celery. Proc. Fl. Stte Hort. Soc. 75: Hyslip, Normn C. 96. Lef miner control on tomtoes in the Indin River Are. Proc. Fl. Stte Hort. Soc. 7: Spencer, Keneth A A clrifiction of the sttus of Liriomyz trifolii (Burgess) nd some relted species. (Dipter: Agromyzide). Proc. Ent. Soc. Wsh. 67: 32-. PESTICIDAL CONTROL OF CABBAGE APHIDS R. B. Workmn Potto Investigtions Lortory University of Florid Hstings Astrct Experimentl nd grower-ville pesticides were tested ginst cge phids, Brevicoryne rssice (L.), infesting russels sprouts nd rutgs in the field during 965, 966, nd 96 t Hstings, Florid. Tretments were mde 7- times t weekly intervls using grower-type equipment. Pesticides giving the est control were Azodrin, dizinon, Di- Syston, Furdn, nd Met-Systox-R. Introduction Six to seven thousnd cres of cge with vlue of out $ million re grown nnully in the Hstings re (). Cge phids, Brevicoryne rssice (L.), re one of the mjor pests ttcking the crop. The phids infest c ge during the erly stges of growth nd if not controlled, uild up to lrge numers cus ing distortion of the leves nd unmrketility of the hed. Activity egins during Novemer nd Decemer with pek phid popultions oc curring in Mrch. Similr conditions hve een reported t Snford, Florid nd the lower Rio Grnde Vlley of Texs (3,). Growers t Hstings generlly follow "preventive" pro grm for the est phid control using regulr Florid Agriculturl Experiment Sttions Journl Series No. 35. contct sprys of - 2 pplictions of systemic insecticides when the plnts re smll. High phid numers on cge fter hed formtion re nerly impossile to control. Aphid control tests conducted in 965, 966, nd 96 t the Potto Investigtions Lortory, Hstings re reported in this pper. Methods nd Mterils Cruciferous crops developing new outer growth through mturity ttrct nd sustin lrge infesttions of cge phids. Numers on cge often decline during this stge of growth. Pimentel (2), in New York Stte, found' higher numers of cge phids on vrieties of russels sprouts, kle, nd roccoli thn on cge. At Hstings, highest numers hve een found on russels sprouts, rutg, roccoli, nd collrds. Brussels sprouts, vriety Long Islnd Im proved, nd rutgg, Americn Purple Top, plnts were grown in seeded nd trnsplnted to field plots. Individul plots were rows wide y 5 feet long with row spcing of inches. Three rows were plnted to cge t 9-inch spcing. The north, inside row ws plnted lterntely to russels sprouts nd rutg t n -inch spcing. Thus, ech plot nd tret ment could e used for evlution of phid nd worm control on different crops. Tretments were pplied s sprys t the rte of gllons per cre nd 3 pounds pressure with -row spryer equipped with 6 hollow-cone nozzles per row. Tretments were mde t weekly intervls during Ferury, Mrch, nd April nd totled