Bethke, James A

Christie, George D. : George D. Christie are graduate students with the Department of Entomology, University of California, Riverside.

Parrella, Michael P

Robb, Karen L.

Several natural enemies show promise - to - controlleafminer against hard Control of Liriomyza trifolii with biological agents and Adult female L . trifolii . insect growth regulators Michael P . Parrella 0 Karen L . Robb George D . Christie 0 James A . Bethke Young Diglyphus larva feeds on leafminer larva , effectively . themum greenhouses to parasitize L . trifolii . A leafmining fly , the major pest of chry - stopping mine development Following is a brief description of parasites santhemums grown for cut flowers and in being reared in our greenhouses . pots , has proved impossible for growers to Diglyphus intermedius ( Girault ) and Di - control with currently available insecticides , glyphus begini ( Ashmead ) . For the purpose even with applications at three - day intervals . of this article , we will discuss the biology of In a search for other methods of pest suppres - these species together under the format of a sion , we have undertaken studies of poten - generalized life cycle for the genus , although of the tially effective natural control agents Diglyphus we are studying them individually . Liriomyza trifolii ( Bur - serpentine leafminer , spp . are characterized by a relatively short gess ) , and have also evaluated insect growth 11 development time - egg to adult in about regulators for their ability to control the lar - days , compared with about 20 days for the val and pupal stages . These materials are leafminer at 78 " F . Adult parasites lay their potentially compatible with natural control Chrysocharis parksi deposits eggs near leafminer larvae ; newly hatched agents because of their low toxicity and host eggs inside leafminer larva , parasite larvae feed externally on the leaf - specificity . where parasites will develop . miner larvae . This effectivelystops larval and Search for natural enemies mine development and is important when considering that the mere presence of mines To determine the parasite fauna associated on a crop such as mums reduces their aesthe - with chrysanthemum greenhouses , we placed tic and , thus , market value . mum plants infested with leafminer larvae In addition , females of Diglyphus spp . ( about 20 larvae per plant ) alongside heavily sting and kill more leafminer larvae than their infested chrysanthemum greenhouses in will emerge from New parasites progeny need for development . After sting - Orange and San Diego counties during per - leafminer pupa parasitized by a larva , the adult parasite feeds on exu - ing Chrysocharis ( left ) . iods of peak fly activity in July and August . date from the dying larva , a phenomenon After five to seven days of exposure , they known as host feeding and a positive aspect were returned to the laboratory , where they in reducing leafminer populations in the of parasites . We were held for emergence greenhouse . Females generally live three to found several species of parasites and are 40 eggs . four weeks and lay approximately conducting biological studies of three of Chrysocharis parksi ( Crawford ) . This them . species is a larval - pupal parasite . It deposits Although our survey of the parasite fauna its eggs inside the leafminer larva , and para - associated with chrysanthemum greenhouses site development is internal . Parasitized is incomplete ( approximately 17 species of leafminer larvae complete their development parasites have been reared from Liriomyza in and drop to the ground , where pupation oc - western North America ) , the parasites recov - curs . Then , instead of adult leafminers ered are considered to be among the most im - emerging from puparia , parasites emerge . portant species parasitizing the leafminer in Chrysocharis develops ( egg to adult ) in field - grown tomatoes and celery in Califor - Tomato bug , Cyrtopeltis modestus , as approximately the same amount of time nia . Under reduced pesticide application is a leafminer predator but also the leafminer . These negative aspects of programs , these parasites move into chrysan - a secondary tomato pest . CALIFORNIAAGRICULTURE , NOVEMBER - DECEMBER 1982 17 Chrysocharis ( allowing complete mine for - spreader , B - 1956 , was added to each material the leaf before dropping to the ground to at 1 milliliter per gallon . IGRs , except meth - mation and possessing relatively long devel - pupate . opment time ) may be offset by the ease with oprene , were applied to plants containing There are still large data gaps , however , which this parasite can be mass - produced for newly hatched larvae . All IGRs , including that need to be filled before the tomato bug release . Parasitized pupae can be instantly methoprene , were also applied to plants con - could be considered for biological control of separated from those unparasitized . Like Di - taining third stage ( mature ) larvae . There leafminer larvae . In addition , the possible glyphus spp . , Chrysocharis females host - were 10 plants for each larval age class for movement of the bug from chrysanthemum feed , killing more hosts than are needed for each treatment . to tomato may limit the areas where it can be After IGR application to newly hatched development of their progeny . used . larvae , plants were placed on greenhouse Feasibilityof parasite release Insect growth regulators benches where larval development contin - ued . When larvae were about ready to Our research is directed toward findingthe Six insect growth regulators ( IGRs ) were best parasites for use in an inundative re - emerge , leaveswere removed and placed on a evaluated for control of the larval and pupal lease - that is , using them as a biological in - thin layer of sand in small glass containers , stages of the leafminer - CGA 77622 ( mode secticide . The low level of mines per plant which were held in an environmental cham - of action is unknown , but believed to be hor - ber at 26.7 " that are acceptable to growers precludessuch C , to 50 to 60 percent relative monal ) , methoprene , RO 13 - 5223E , RO humidity , and 14.5 - hour photophase . releases for long - term suppression of L . tri - 13 - 5223W ( juvenile hormone mimics ) , Bay Instead , parasites would be released folii . Pupating larvae were sifted out and placed in SIR 8514 , and dimilin ( chitin inhibitors ) . All ventilated containers on moist sand under the into mum greenhouses during the initial five these materials are characterized as nontoxic same conditions . These were checked daily to six weeks of crop development . The fo - to mammals and relatively specific to the for emergenceof adults . After liage on plants during this period is not pres - IGRs were ap - target pest ; they show little or no effect on ent when the final flowers are cut . plied to plants that contained third stage lar - nontarget organisms . Ideally , the parasites would keep the leaf - vae , leaves were removed and handled in the Standard chrysanthemum plants ( three - miner population at low levels without appli - same way . leaved , 30 days old ) of the variety ' White cation of insecticides . After the sixth week , In addition , methoprene was evaluated as Hurricane ' were exposed to large colonies of pesticides would be used , if needed , to leafminers for one hour , so that all oviposi - a soil drench in 5 - inch pots filled with moist protect marketable foliage - preferably , soil . The rate used was equivalent to 2.5 tion , subsequent egg hatch , and larval devel - ounces of formulated material per 100gallons opment in all plants would be synchronous . insecticides that are compatible with natural per 1 , OOO square feet . Five pots were treated IGRs were applied as foliar sprays to runoff enemy releases . with methoprene , and five ( controls ) with 60 psi . A sticker - with a 1 - gallon sprayer at Other natural agents TABLE 1 . Effect of selected insect growth regulatorson newly hatched larvaeof In conjunction with Harry Kaya , Associate Liriomyza trifolii ( Burgess ) Nematologist at U.C . , Davis , and Carolyn Posttreatmentcount $ Pickel , Cooperative Extension Area Special - Total Total ist , we conducted preliminary efficacy trials Total larval emerging Mean emerging Mean with a predaceous nematode , Neoaplectana pretreatment larvae percent adults percent carpocapsae ( Weiser ) , for leafminer control . Material Rate * countt 110 plants control 110 plants control This nematode is effective against several Ib % % soil - inhabiting insects , and is being sold com - CGA 77622 5SC 0.5 181 0 100.0a . . . . . . mercially in northern California as an alter - RO 13 - 52231E 0.8 174 141 19.5b 41 74.0a RO 13 - 522350W 0.8 108 84 26.0b 68 40.8b native method of controlling leafminers in BAY SIR 8514 0.5E 0.5 178 115 29.7b 99 41.2b chrysanthemums . The nematode is applied as Control . . . 171 150 11.3b 120 22.3b ~ ~ ~ a soil drench and may attack leafminers in Dimilin 25W 0.5 217 187 20.9b 164 34.3b two ways : after mature larvae drop to the soil ' Pounds active ingredient per 100 gallons water t10 plants per test material with mean f SE = 17.2 + 1.4 larvae per plant . before pupation , and as adults emerge from $ Mean percent control was calculated with individual plants as replicates . Means followed by the same letter are not the puparia . Preliminary screeningtrials with significantly different ( p > 0.05 ) , Duncan's new multiple range lest . No data transformation was necessary . N . carpocapsae at 9 to 400 per square centi - meter of soil surface did not provide consis - TABLE 2 . Effect of selected insect growth regulatorson late third - stagelarvae of Liriomyza trifolii ( Burgess ) tent results . Further evaluations are planned . Biologicalstudies also are being conducted Posttreatmentcount $ with the tomato bug , Cyrtopeltis modestus Total Total Total larval emerging Mean emerging Mean ( Distant ) , a mirid predator of leafminer lar - pretreatment larvae percent adults percent vae and other insects . This insect is com - Material Rate ' countt 110 plants control 110 plants control monly found in tomato fields in southern Ib % % California , where it is considered a secondary CGA 77622 5SC 0.5 192 0 100.0a . . . . . . pest , primarily feeding on the stems . How - RO 13 - 52231E 0.8 222 216 3.5c 13 94.2a ever , the tomato bug does not feed on chry - Methoprene 5E 4.0 212 176 17.4b 17 92 . la RO 13 - 522350W 0.8 171 156 11.9bc 68 63.76 santhemum . Later stages and adults readily BAY SIR 8514 0.5E 0.5 218 208 3.7c 170 19.5 ~ pierce leafminer larvae within the mesophyll Control 157 144 9 . lc 129 18.6 ~ of a chrysanthemum or tomato leaf . The bug Dirnilin 25W 0.5 247 231 9.6 ~ 217 13.5 ~ quickly immobilizesthe larva , sucking out its ' Pounds active ingredient per 100 gallons water . ti0 plants per test material with mean f SE = 20.3k 1.2 larvae per plant . contents . In addition , the tomato bug attacks * Mean percent control was calculated with individual plants as replicates . Means followed by the same letter are not late third stagelarvae that have emerged from significantly different ( p > 0.05 ) , Duncan's new multiple range test . No data transformation was necessary . 18 CALIFORNIA AGRICULTURE , NOVEMBER - DECEMBER 1982 water . After treatment , 20 mature larvae , Those IGRs that provided the best control within the leaf . However , some materials which had just emerged from chrysanthe - of emerging ( CGA - 77622 , RO 13 - 5223E , and metho - provided significant control mum leaves to pupate , were added to the soil adults . These IGRs generally provided better prene ) are currently being evaluated for in each of the 10 pots . Each pot was capped control when applied to leaves containing phytotoxicity to chrysanthemums and for with a ventilated cage and checked daily for mature larvae rather than to those containing compatibility with selected natural enemies adult emergence . Water was added to the soil newly hatched larvae ; RO 13 - 5223E and of the leafminer . whenever necessary to maintain a consistent methoprene provided greater than 90percent levelof moisture . All pots were kept inan en - control of adult emergence . As a soil drench Michael P . Parrella is Assistant Professor , Karen vironmental chamber as in other treatments . application , methoprene provided only 31 L . Robb and George D . Christie are graduate CGA 77622 was the only IGR to provide percent control of emerging adults , which students , and James A . Bethke is Laboratory 100 percent control of newly hatched and was not significantly different ( pX . 05 , T Assistant . All are with the Department of Ento - mature larvae ; all larvae were killedwhile still test ) from the control ( 19 percent ) . mology , University of California , Riverside . Following are articles appearing in California Agriculture , Volume 36 , Numbers 1through 12 , 1982 INDEX January through December 1982 ( listing first author only ) . ANIMAL SCIENCE Potential market for plums and New wasp attacks navel orange - Somatic cell genetics : Goats grazing in chaparral - nectarines in Japan - worm - Legner May - Jun manipulating plants through Sidahmed May - June Moulton Sep - Oct single - cell techniques Reducing pesticide treatments in Innovationsin plant breeding : Observations on Bodmin - Trees as energy crops celery - new concepts in whole - plant Standiford May - June Nu - Pulse milking system - Van Steenwyk Sep - Oct genetics Shultz Mar - Apr Agricultural applications : Single citrus budwood treatment INSECT AND PEST MANAGEMENT integrating conventional and against insects , mites - CULTURAL PRACTICES , JUI molecular genetics Elmer Ants in almond orchards - FERTILIZAT10N , IRRICATlON Reil Jul 75 years of citrus Spider mites can reduce Advantages of polyculture strawberry yields - research Nov - Dec cropping - Altieri Jul Applying parasitic nematode to Sances Jan - Feb ( various authors from Citrus control carpenterworm in fig Research Center - Riverside ) Celery yields and uniformity - Lindegren Nov - Dec trees Trapping black cutworm in straw - Introduction and history affected by pre - transplant berries - Clement - Welch Mar - Apr practices Biological control of ice plant Jâ??l Breeding and development - Tassan Sep - Oct scales Cultural practices Whitefly problem in southern Cal - Chemical and cultural control of ifornia - Johnson - kikuyugrass in turf - Cabbage aphid control Sep - oct Diseases and their control Cudney Jan - Feb McCalley May - June Insect pests and their control Iy - transmitted disease Whitef Cotton growth related to plantâ??s - Duffus Nov - Dec OTHER complex Chemicals losing effect against water status - Grimes Nov - Dec g - grape mealybu Flaherty May - June PLANT DISEASES Cumulative effects of ethephon Disease - induced potassium as fruit thinner on French prune deficiency and verticillium wilt Chemical control of phomopsis trees - Sibbett Sep - Oct Detection of dicofol - resistant incotton - Ashworth Sep - Oct - rapevine cane and leaf spot n - spider mites in cotto 8ucuzza Dennehy Nov - Dec Mar - APr Desert soil compaction reduces Drip irrigation in young almond plant cover - Adams Sep - Oct â?? Eureka â?? . sweet Dotato resistant orchards - Fereres Sep - Oct Gypsy moth : here again - Hoy Jul to soil rot ( pox ) - Donations for agricultural Late - fall nitrogen application in Improved parasites for filth fly Scheuerman Jan - Feb research , July 1,1980 - - vineyards is inefficient - Legner Sep - Oct control June30,1981 Jan - Feb GraDevinesshow seasonal differ - Peacock Jan - Feb ences in susceptibility to Large - scale releasesof pesticide - Ethephon may speed up opening eutypa - Petzoldt Midwinter irrigation can reduce resistant spider mite predator - Mar - Apr of late - planted cotton - deep bark canker of walnuts - HOY Jan - Feb Weir Sep - Oct Tarping to control wilt in pis - Teviotdale May - June tachios - Ashworth Liriomyza trifolii control with bio - MaY - Jun Growing with MasterGardeners - Progress report on narrow - row logical agents and chemicals - Grieshop Jul - Curley Sep - Oct cotton SPECIAL PRESENTATIONS Parrella Nov - Dec Growth control of laurel fig with Trunk injection corrects iron Measuring brown mite injury to Genetic engâ??ineering of chlorflurenol - Hield Nov - Dec olants Aua deficiency in plum trees - avocados - Sances May - Jun r - - - 0 ( Variousauthors from U.C . depart - Master plan for drainage in S J Yoshikawa Mar - Apr valley - Hanson ments active in molecular biology Midsummer walnut aphid out - May - Jun research ) Vineyard cultural practices may - Sibbett May - Jun breaks help reduce botrytis bunch rot - Role of the university in Rebaudiâ??s stevia : natural Savage Mar - Apr Mites : primary food for two genetic engineering noncaloric sweeteners - predators in San Joaquin Valley Genetic enaineerina : the new Shock SeD - Oct - Gonzalez Mar - Apr cotton ECONOMICS AND MARKETING techniquesand thek potential Plant breeding : and Rice sterility varies with area and Factors affecting sugarbeet Monitoring and modeling oriental limitations variety - Board Jan - Feb yields - Wallace Jul fruit moth - Rice Jan - Feb Plant genes : understanding Two insects offer potential mechanisms of gene Hired workers on California Monitoring and modeling San biological control of common farms - Martin Sep - Oct Jose scale - Rice Jan - Feb expression purslane - Clement Mar - Apr Gene vectors : crossing natural Monitoring aphid infestations on On - farm alcohol fuel Update : oat hay variety trials - barriers to genetic broccoli - Trumble Nov - Dec production - Meo Jul manipulations Schoner Jan - Feb CALIFORNIA AGRICULTURE , NOVEMBER - DECEMBER 1982 19