Observations on the biology and host specificity ofEpiblema strenuana [Lepidoptera,Tortricidae], a potential biocontrol agent forParthenium hysterophorus [Compositae]

The tortricid mothEpiblema strenuana (Walker), which attacksAmbrosia spp. over most of North America, is shown to have the annual weedParthenium hysterophorus L. [Compositae] as its main host in northern Mexico. The larvae produce galls in the stems and growing-points which can considerably stunt growth when young plants are attacked. In tests it was shown to have a restricted host-range and not to damage any composite of economic importance. Its release in Australia for trial as a biological control agent againstP. hysterophorus has been approved.      

Host specificity ofAceria (Eriophyes) malherbe, [Acari: Eriophyidae], a biological control agent for the weed,Convolvulus arvensis [Convolvulaceae]

The host specificity of the gall mite,Aceria (Eriophyes) malherbe (Nalepa), from Greece was studied under quarantine conditions at Albany, California USA. Of the species, ecotypes, or strains tested, onlyConvolvulus andCalystegia spp. supported gall formation and mite reproduction. Although 2 of the native, North AmericanCalystegia species that served as laboratory hosts are threatened or endangered species,A. malherbe is considered safe for release in the USA as a biological control agent of the weed,Convolvulus arvensis (L.).      

Evaluation ofMicrothrix inconspicuella, [Lepidoptera: Pyralidae], a potential biological control agent forEmex australis in Australia,carried out in apple orchards in South Africa

Host specificity tests carried out in the laboratory in Australia during 1977, showed thatMicrothrix inconspicuella Ragonot could develop on young apple leaves (Harley et al., 1979). Field studies in unsprayed apple orchards in South Africa showed that some feeding occurred, but fewer than 40% of late instar larvae developed to adults when confined in sleeves on apple tree branches. No feeding or survival occurred in large field cages or in the open. Adults which developed from apple fed larvae were smaller, deformed, occasionally mated and laid fertile eggs but their progeny did not feed or develop on apple fruit or leaves. In conclusion,M. inconspicuella larvae did not develop on apple fruit or leaves in the field, damage was mainly limited to apples already injured and feeding on leaves was minimal. Under normal pest control practicesM. inconspicuella populations did not survive on any part of the apple tree or onE. australis growing under the trees.      

Biological control of thrips [Thysanoptera: Thripidae] on greenhouse cucumber byAmblyseius cucumeris

The predatory miteAmblyseius cucumeris (Oudemans) [Acarina: Phytoseiidae] was evaluated as a biological control forThrips tabaci Lindeman andFrankliniella occidentalis (Pergande) [Thysanoptera: Thripidae] on greenhouse grown seedless cucumber.A. cucumeris spread throughout the greenhouses and provided control of both species of thrips.A. cucumeris adults persisted on plants for 7 weeks in the virtual absence of prey, and increased numerically in response to increases in prey population. On the basis of these resultsA. cucumeris is recommended as a useful biological control forT. tabaci andF. occidentalis on greenhouse cucumber. Publication No. 361, Agassiz Research Station, Agriculture Canada, Agassiz, B.C. Canada VOM 1AO.     

Bionomics ofTetrastichus sesamiae [Hymenoptera: Eulophidae], a pupal endo-parasitoid ofMaruca testulalis [Lepidoptera: Pyralidae]

The biology and behaviour ofTetrastichus sesamiae Risbec, a pupal endoparasitoid ofMaruca testulalis Geyer, were studied under laboratory conditions. Most adults emerged from the host pupae between 08.00 h and 09.00 h and mating and oviposition started almost immediately. Both ♂♂ and ♀♀ mated repeatedly, and each ♀ could lay eggs for up to 6 days and in up to 5 host pupae. Progeny production ranged from 0–263 offspring per ♀ and adult longevity was from 4.3–13.9 days. The quality of food available to the adults was a major factor influencing progeny production, and longevity. The species was capable of parasitizing and completing development on pupae of such other major Lepidopteran crop pests asChilo partellus Swinhoe,Busseola fusca Fuller,Eldana saccharina Wlk andSpodoptera exempta Wlk, an important finding for biological control of these pests under intercropped agro ecosystems. Apart from parasitism, ♀♀ ofT. sesamiae also caused considerable mortality by stinging, and presumably paralyzing, host pupae without ovipositing.      

Biological studies ofBrachyserphus abruptus [Hym.: Proctotrupidae], a nitidulid parasite

Data are presented on survival, fecundity, and hosts ofBrachyserphus abruptus (Say), a solitary internal parasite of nitidulid (sap beetle) larvae. In the laboratory these wasps have been successfully reared fromCarpophilus hemipterus (L.),C. freemani Dobson,C. lugubris Murray,Stelidota geminata (Say),S. octomaculata (Say),S. ferruginea Reitter,Glischrochilus quadrisignatus (Say),Lobiopa insularis (Castelnau), andHaptoncus luteolus (Erichson). Field collections ofB. abruptus have been made fromS. geminata, S. octomaculata, C. hemipterus, C. lugubris, L. insularis andH. luteolus. Oviposition continues throughout most of the adult female's lifetime. Under laboratory conditions life expectancy of females wasca. 6 days. Mean number of progeny reaching adulthood per female was 57, with a 1∶1 sex ratio. First and 2^nd instar nitidulids were suitable for successful development ofB. abruptus. Third instars were attacked byB. abruptus but were not successfully parasitized. Parasite development required 29 days in 1^st instar hosts and 27 d. in 2^nd instars. Percent parasitism in 1^st instarC. hemipterus averaged 65% and for 2^nd instar 45%. After parasitism, larvae ofC. hemipterus surviving to become adults averaged 0.6% for 1^st instar, 9.3% for 2^nd instar, and 90% for 3^rd instar. This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation for its use by The Ohio State University.     

Biological control of the weed,Chromolaena odorata [Asteraceae], byPareuchaetes pseudoinsulata [Lep.: Arctiidae] on Guam and the northern Mariana Islands

Chromolaena odorata L. is a major weed of tropical plantations and pasture lands.Pareuchaetes pseudoinsulata Rego Barros [Lep.: Arctiidae] was mass-reared and released to control the weed on the Mariana Islands of Guam, Rota, Tinian and Saipan in the western Pacific. One year following establishment ofP. pseudoinsulata on Guam, the weed was reduced 100% at 3 of 4 sites monitored with fixed quadrats. Seed production was prevented if defoliation occurred prior to the beginning of the flowering season. If defoliation occurred shortly after flowering began, the developing seeds were eaten byP. pseudoinsulata or there was a significant reduction in weight and germination of seeds that matured. Eighteen months after establishing on Guam,P. pseudoinsulata had defoliated approximately 25,000 hectares of the weed. This is the 1^st report on the quantitative impact of any control agent forC. odorata, and though the long term effect of the insect is still unknown, these results are encouraging.     

Introduction,colonization and establishment ofLysiphlebus testaceipes [Hymenoptera: Aphidiidae], in Argentina

The introduction, colonization, and establishment ofLysiphlebus testaceipes (Cresson) for the biological control ofSchizaphis graminum (Rondani). in Argentina is briefly discussed.     

Biological control ofAphis pomi [Hom.: Aphididae] ofAphidoletes aphidimyza [Dip.: Cecidomyiidae]; a predator-prey model

Predation ofAphis pomi DeGeer [Hom.: Aphididae] byAphidoletes aphidimyza (Rondani) [Dipt.: Cecidomyiidae] was simulated in Michigan apple orchards using a computer and output validated against field data collected from sleeve cages enclosing aphid infested apple terminals. Lower and upper temperature thresholds for development were 2.9 and 35°C for nymphs ofA. pomi with a mean immature developmental period of 162.3 heat units. Median survivorship of adultA. pomi was 364.3 heat units with an average fecundity of 60.7 offspring per female.A. aphidimyza egg and larval lower threshold and developmental periods were 10.5 and 25.5, 8.1°C and 65.5 heat units, respectively. Larval functional response showed Type II behavior with a y-asymptote of 45 aphids killed per predator. Multiple generation model runs performed under different initial predator: prey densities indicated that current critical predator: prey ratios used in the field for control decisions may underestimate predator efficacy.      

Host-specificity and virus-vector potential ofAphis chloris [Hemiptera: Aphididae], a biological control agent for St John's wort in Australia

Under laboratory conditionsAphis chloris Koch has been demonstrated to be specific to plants belonging to the genusHypericum. It can effect severe damage to its principal host,H. perforatum L., and shows good potential for contributing to the control of this noxious weed. Other species ofHypericum are less favoured hosts ofA. chloris and would not be endangered by it. A. chloris shows a high level of host-discrimination and does not transmit persistent viruses between non-host plants. Whereas in the laboratory it is capable of transmitting non-persistent viruses, it would contribute only marginally to the risk of virus transfer posed by the Australian aphid fauna as a whole, and its release would not necessitate changes to existing control practices, where these are required to reduce plant virus transmission. As a consequence,A. chloris is considered safe for release againstH. perforatum in Australia.      

Host-specificity of a root borer,Bembecia chrysidiformis [Lep.: Sesiidae], a potential control agent forRumex spp. [Polygonaceae] in Australia

Bembecia chrysidiformis (Esper) [Lep.: Sesiidae] was examined for its natural history and specificity toRumex spp. (Polygonaceae) which are weeds in Australia. Adults of this southern European insect appear in late spring to summer. Eggs are laid on the dried, seed bearing stems of perennialRumex plants. The larvae tunnel inside the root during summer through to the next spring. In nature, the larvae are round inRumex species of the subgeneraRumex andAcetosa. In host-specificity tests with 1st instar larvae, the roots of a number of genera within thePolygonaceae were attacked. Larvae died on a range of plants from other families except inPersea americana Miller(Lauraceae), Helianthemum nummularium (L.) Miller (Cistaceae) andQuercus ilex L. (Fagaceae) where larvae fed on the stems. The insect was judged safe for release in Australia by assessing aspects of its biology, its known host plants, and the lack of reported attack on other plants.      

Biology ofTyta luctuosa [Lep.: Noctuidae] and its potential value as a biological control agent for the weedConvolvulus arvensis

The biology of the noctuid,Tyta luctuosa (Denis & Schiffermüller) (Lep.: Noctuidae), a defoliator of field bindweed,Convolvulus arvensis L., was studied in southern Europe.T. luctuosa is widely distributed and feeds on both thick stands and scattered host populations growing in a diversity of habitats. It undergoes 2 and perhaps a partial 3rd generation/year in southern Europe and is active during most of the growing season ofC. arvensis. In the laboratory the total time from egg to adult averages 45.6 days. There are 5 larval instars. Adult females deposit on average over 400 eggs. The larvae being able to feed and develop on native North AmericanCalystegia spp. in the laboratory, there are some reservations about its release in North America. However, the moth has potential value as a biological control agent for field bindeed in the western USA where it would fill an almost unoccupied niche.      

Biological control by Clonostachys rosea as a key component in the integrated management of strawberry gray mold

Gray mold, caused by Botrytis cinerea, is an important strawberry disease. As gray mold control is difficult, there is a need to evaluate integrated methods to successfully manage the disease. The efficiency of integrating Clonostachys rosea sprays, fungicide sprays, and crop debris removal to manage gray mold was evaluated in field experiments conducted in 2006 and 2007. Leaf colonization by C. rosea (LAC), average number of B. cinerea conidiophores (ANC), gray mold incidence in both flowers (Iflower) and fruits (Ifruit), and yield were evaluated weekly. In both years, LAC was higher in the treatments with no fungicide. When compared to the check, ANC, Iflower and Ifruit were most reduced in treatments that included C. rosea sprays. Maximal reductions were achieved with the combination of C. rosea sprays, fungicide sprays and debris removal (96.62%, 86.54% and 65.33% reductions of ANC, Iflower and Ifruit, respectively). Otherwise, maximal yield (103.14% increase as compared to the check) was achieved with the combination of the three treatments. With just C. rosea sprays, ANC, Iflower and Ifruit were reduced by 92.01%, 68.48% and 65.33%, respectively, whereas yield was increased by 75.15%. Considering the individual effects, application of C. rosea was the most efficient treatment. Chemical control was effective only in plots without debris removal. Elimination of crop debris was the least effective method in reducing gray mold incidence in both flowers and fruits. The integrated control approach enhanced the efficacy of the individual methods of gray mold control and provided high strawberry yield. An important component of this integrated approach it the biological control with C. rosea.     

Biological control of Lygus lineolaris by Peristenus spp. in strawberry

Peristenus digoneutis Loan (Hymenoptera: Braconidae) was introduced to the US for biological control of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), and has since spread through much of the northeast. The purpose of this study was to determine if P. digoneutis and a native congener, Peristenus pallipes (Curtis), parasitize L. lineolaris in strawberry (where it is a key pest), and what factors relate to parasitism levels. During 1997–1999 we monitored parasitism on 17 strawberry farms in 14 counties in eastern and western New York State. We found that in eastern NY (where P. digoneutis has been established since the early 1990s), overall mean parasitism was 19.7% (ranging from 0 to 70%), mostly by P. digoneutis. Mean parasitism was significantly lower (12.3%, ranging from 0 to 58%) in western NY (where P. digoneutis was first recorded in 1999), and was mostly by P. pallipes. P. pallipes parasitism was significantly lower in eastern than western NY, suggesting the potential for competitive interaction with P. digoneutis. The insecticide regime of a farm was an important factor influencing parasitism rate, which was 5- to 6.5-fold higher on organic or casually sprayed farms than on intensely treated farms, though pest density under these three regimes was not significantly different. L. lineolaris density, and parasitism rate in nearby alfalfa and abandoned fields were also significant factors for parasitism in strawberry.     

Biological control of plant pathogens in Brazil: application and current research

There are several examples of successful isolation, selection and development of antagonists of plant pathogens available for commercial use: mild strains of Tristeza virus of citrus for the control of Tristeza virus of citrus through preimmunization; Acremonium alternatum and A. persicinum for the control of tar spot of coconut (Catacauma torrendiella and Coccostroma palmicola); Trichoderma spp. for the control of Phytophthora cactorum on apple after soil treatment with formaldehyde and Dicyma pulvinata for the control of South American leaf blight (Microcyclus ulei) on rubber trees (Hevea brasiliensis) associated with polyclone plantations, are just a few. In an advanced stage of development there are for example: Bacillus subtilis for seed treatment and control of Sphaerotheca fuliginea on zucchini squash; Trichoderma spp. for soilborne pathogens; and Gliocladium roseum for the control of Botrytis cinerea in greenhouse cultivated strawberry.The author is with EMBRAPA/CNPMA, C.P. 69, 13820-000, Jaguariúna, SP-Brazil     

The incidence and use of Oryctes virus for control of rhinoceros beetle in oil palm plantations in Malaysia

The rhinoceros beetle, Oryctes rhinoceros, has emerged as a serious pest of oil palm since the prohibition of burning as a method for maintaining estate hygiene in the 1990s. The abundance of beetles is surprising given that the Malay peninsula was the site of first discovery of the Oryctes virus, which has been used to effect good as a biological control agent in other regions. A survey of adult beetles was carried out throughout Malaysia using pheromone traps. Captured beetles were examined for presence of virus using both visual/microscopic examination and PCR detection methods. The survey indicated that Oryctes virus was common in Malaysia among the adult beetles. Viral DNA analysis was carried out after restriction with HindIII enzyme and indicated at least three distinct viral genotypes. Bioassays were used to compare the viral strains and demonstrate that one strain (type B) is the most virulent against both larvae and adults of the beetle. Virus type B has been cultured and released into healthy populations where another strain (type A) forms the natural background. Capture and examination of beetles from the release site and surrounding area has shown that the spread and persistence of the applied virus strain is accompanied by a reduction in palm frond damage.     

Host specificity testing ofRhodometra sacraria [Lep.: Geometridae], a possible biological control candidate forEmex australis in Australia

The foliage feeding geometridRhodometra sacraria L. was collected onEmex australis Steinheil in South Africa, cultured, then tested as a possible biological control agent forE. australis, in Australia. Tests on its host specificity were carried out in South Africa and Australia.R. sacraria was specific to plants of the familyPolygonaceae rather than toE. australis. Request for the reintroduction and release ofR. sacraria into Australia has not been made.      

Chamaesphecia doryliformis [Lep.: Sesiidae], a second root borer for the control ofRumex spp. [Polygonaceae] in Australia

The host-specificity and biology ofChamaesphecia doryliformis (Ochsenheimer) [Lep.: Sesiidae] are described and the insect is assessed for its potential as a biological control agent for weeds of the genusRumex (Polygonaceae) in Australia. The insect is found in the western Mediterranean region, chiefly in north Africa. Adults emerge from pupation in late spring to summer when they lay eggs. The larvae feed inside the roots of post-reproductive plants belonging to the subgeneraRumex andAcetosa. In host-specificity tests 1^st instar larvae attacked only plants of thePolygonaceae. The insect was judged safe to release in Australia after assessing its level of host-specificity, and attributes of its biology which indicate that native AustralianPolygonaceae will not be endangered.      

Increases in densities of the citrus red mite,Panonychus citri [Acarina: Tetranychidae], in association with the Argentine ant,Iridomyrmex humilis [Hymenoptera: Formicidae], in southern California citrus

We monitored the activities of the Argentine ant,Iridomyrmex humilis (Mayr), in 3 citrus orchards during 1984 and 1985. We also monitored densities of citrus red mite,Panonychus citri (McGregor), the adult spider mite destroyer,Stethorus picipes Casey [Col.: Coccinellidae], and the predatory mite,Euseius tularensis Congdon [Acarina: Phytoseiidae] during the same period in ant-present and ant-free plots in each orchard. I. humilis was excluded for at least 9 months from trees pruned 60 cm from the ground following a basal application of 1 or 2 % chlorpyrifos 4 EC. Autumn densities ofP. citri in these ant-free plots were significantly lower than those in the plots infested withI. Humilis. S. picipes appeared to be the most important predator, maintaining lowP. citri densities on citrus in southern California in the absence ofI. humilis activity.S. picipes densities increased numerically in response to the early spring and late autumn increases in the density ofP. citri populations. However, in the presence ofI. humilis activity, effective predation was apparently inhibited. Densities ofE. tularensis were unaffected by the presence ofI. humilis, nor didE. tularensis respond to spring or autumn increases in the density ofP. citri populations in any of the orchards.      

Biological control of the water fernSalvinia molesta infesting a lily pond in Bangalore (India) byCyrtobagous salviniae

The aquatic fernSalvinia molesta D.S. Mitchell is a serious weed in India, espacially in the state of Kerala. The weevilCyrtobagous salviniae Calder and Sands (Col.: Curculionidae) was introduced from Austrialia and successfully controlled the weed infesting a lily pond at Bangalore. Contribution No. 174/85 of the Indian Institute of Horticultural Research, Bangalore, India.