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Elhadi M. Yahia, Dora Ortega, Pamela Moreno, and Alejandro Martinez

Previous work in our laboratory and also reported in this meeting has indicated that insecticidal controlled atmospheres at high temperatures (0.5% O2 + 50% CO2 at 44-55°C and 50% RH) are very effective in causing in vitro mortality of eggs and third instar larvas of Anastrepaha ludens and A. obliqua. This work is a follow up that evaluated the effect of such atmospheres on the in vivo mortality of third instar larvas artificially infested in mango. Atmospheres evaluated included 0% O2+ 50% CO2 at 35, 37, 39, 40, 42, 43, 44, 45, 46, 47, 48, and 49°C for 160 min. Treatments at 35-40°C caused 100% mortality of larvas of A. obliqua, but not of A. ludens. Temperatures of 42 to 49°C caused 100% mortality of larvas of both species. Statistical analysis to calculate the probit 9 will be discussed.

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Pablo Velasco, Rosa A. Malvar, Ana Butrón, Pedro Revilla, and Amando Ordás

Pink stem borer (Sesamia nonagrioides Lef.) is one of the most important insect pests of corn (Zea mays L.) in southern Europe. The objectives of this work were to determine the level of resistance in different sweet corn inbreds and to identify sources of resistance to ear feeding by the pink stem borer. Twenty-eight sweet corn (su1 and su1se1) inbreds and four resistant field corn (Su1Se1) inbreds were evaluated for ear resistance at different sowing dates, under two methods of artificial infestation. There were significant differences between infestation methods for ears with damaged grain, husks, cobs, and shanks. The inbred×infestation method interaction was significant for general appearance of the ear. The most resistant inbreds were identified by using mean comparisons and principal component analysis of ear damage traits. All inbreds were damaged. Hence, resistance was incomplete and in need of improvement. EP59, H3, I5125, IL767b, and V7726 were the most resistant sweet corn inbreds, which did not differ significantly from A635, the most resistant field corn inbred. General appearance of the ear appears to be a good indicator of pink stem borer resistance and can be used in preliminary evaluation. Variability exists in the resistance of these sweet inbreds to the pink stem borer and the use of field corn inbreds may not be necessary in the improvement of resistance, although further research is needed to determine if the sources differ in the pertinent genes conferring resistance.

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Raymond A. Cloyd, Daniel F. Warnock, and Keith Holmes

An affordable device comprised of off-the-shelf parts, initially called the “Small Insect Aspirator” was developed to gently collect western flower thrips, Frankliniella occidentalis (Pergande), from a rearing colony for use in insecticide efficacy trials. This device allows for a designated number of thrips to be placed onto any experimental test plant. The device is a battery-motorized driven aspirator comprised of two pieces of copper tubing (6.0 mm in diameter) attached to a copper housing, which contains a threaded plastic lid and glass vial (20-mL). The aspirator is fully portable when attached to a battery-driven vacuum device, which allows researchers to efficiently collect thrips in outdoor field situations. When turned on, the vacuum gently pulls western flower thrips (adult and larval stages) through the copper tubing and deposits them into the collection vial. The vial is then detached and sealed with a threaded lid until the collected thrips are deposited onto experimental test plants.

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Raymond A. Cloyd, Cindy L. Galle, Stephen R. Keith, and Kenneth E. Kemp

longevity of selected miticides after test plants had been treated before being artificially infested with TSM. Expt. 1 determined miticide efficacy on the nymphs and adults, which were pooled in the final analysis because we only evaluated miticides with

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Virginia M. Moore and William F. Tracy

development significantly enough to constitute a separate environment. To evaluate resistance to corn earworm, ears were artificially infested with corn earworm eggs, since corn earworm pressure is unpredictable in south central Wisconsin. Inoculation took

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Raymond A. Cloyd and Amy L. Raudenbush

, and preserve longevity and host suitability. Each cut flower was artificially infested with 20 adult western flower thrips (24- to 48-h old) obtained from laboratory-reared colonies in the Department of Entomology at Kansas State University, Manhattan

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K.C. Shellie and R.L. Mangan

Market demand exists in the United States for fresh mango (Mangifera indica L.) fruit weighing >700 g, yet fruit of this size cannot be imported for lack of a quarantine treatment against fruit flies (Diptera: Tephritidae). Therefore, the objectives of this research were to evaluate the influence of fruit infestation method on mortality of late third instar, fruit fly larvae after fruit were immersed in hot water, and to generate dose mortality and fruit quality data for mangoes >700 g. Results suggested that artificial infestation is preferable to cage infestation because artificial infestation eliminates the direct influence of fruit weight loss on the heat dose delivered to the fruit center. Other advantages of artificial over cage infestation include: fruit maturity at treatment is similar to commercial application, mortality of untreated control fruit can be calculated, larval maturity is uniform and observable, and larvae can be placed into the slowest heating part of the fruit. Infesting with 50 rather than 25 larvae per fruit was preferred because the number of larvae placed into the fruit did not influence mortality and twice as many larvae were evaluated using the same number of fruit. The dose mortality and fruit quality data generated in this research suggest that immersion in water at 46.1 °C for 110 minutes may provide Probit 9 level quarantine security against Mexican fruit fly (Anastrepha ludens Loew) for mangoes weighing up to 900 g without adversely affecting fruit market quality.

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S.Z. Islam, M. Babadoost, and Y. Honda

A study was conducted in the greenhouse to investigate the effects of red light (600-700 nm) on the subsequent occurrence of seedling infection of bell pepper, pumpkin, and tomato caused by Phytophthora capsici. Three- or 4-week-old seedlings were inoculated with zoospores or transplanted into pots filled with artificially infested soil mix. Red light treatment of seedlings reduced Phytophthora damping-off by up to 79%. Only 21% to 36% of red light-treated seedlings became infected, whereas 78% to 100% of the control seedlings, grown either in natural daylight (NDL) or under white light (WL), became infected and died. The height, and fresh and dry weight of seedlings treated with red light were significantly higher than those grown under NDL or WL.

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Mark W. Farnham and Kent D. Elsey

Resistance of a Brassica oleracea germplasm collection (broccoli, Italica Group; cauliflower, Botrytis Group; and collard and kale, Acephala Group) to silverleaf whitefly (SLW; Bemisia argentifolii Bellows and Perring) infestation was evaluated using several measures of insect infestation (including adult vs. nymph counts) taken at plant growth stages ranging from seedling to mature plant. An initial study was conducted in an outdoor screen cage artificially infested with the SLW adults; subsequent field trials relied on natural infestations. The glossy-leaved lines (`Broc3' broccoli, `Green Glaze' collard, and `SC Glaze' collard) had low SLW infestations in cage and field tests. SLW adult counts were less variable than similar comparisons using nymphal counts, although adult and nymph counts were positively and significantly correlated at late plant stages. Based on this study, comparing relative SLW adult populations would be a preferred criterion for identifying B. oleracea resistance to this insect.

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Richard L. Bell and L. Claire Stuart

Four genotypes of pear (Pyrus spp.) of East European origin, a susceptible control, `Bartlett' (P. communis L.), and a moderately resistant control, NY 10352 (P. ussuriensis Maxim. × P. communis B C1 hybrid), were artificially infested with pear psylla (Cacopsyll a pyricol a Foerster) nymphs in the laboratory. Ten neonate first instars were placed on each of the two youngest leaves of four small trees per genotype. On PI 506381 and PI 506382, wild seedlings of P. nivalis Jacq., all nymphs died within 5 days. Mortality and development of nymphs on PI 502173, a wild P. communis seedling, was similar to that observed on `Bartlett', with 43% and 45% of the nymphs surviving to adulthood, respectively. On `Karamanlika' (PI 502165) and NY 10352, 15% of the nymphs developed into adults. Increased mortality and delayed development of nymphs was associated with feeding inhibition. The mode of host plant resistance to pear psylla nymphs in these accessions of East European pear is, therefore, similar to that previously characterized for NY 10352, in which the resistance is derived from germplasm of East Asian origin.