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Curtis H. Petzoldt, Stephen Reiners, and Michael P. Hoffmann

The document Cornell Integrated Crop and Pest Management Guidelines for Commercial Vegetable Production was revised in 1999 to become inclusive and integrative of all aspects of crop and pest management. As an adjunct to the printed publication, additional information was presented in tables at an Internet web site. Links on the web site were made to other sites with more detailed information on specific topics, such as photographs of pests and diagnostic information, soil fertility testing, cover crops, environmental impact of pesticides, pesticide labels, and images, sources, and life cycles of beneficial insects. The revision and web site have proven to be popular with cooperative extension staff and the vegetable industry in New York.

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Jeffrey Gardner, Michael P. Hoffmann, and Margaret E. Smith

Trials were conducted in 1997 and 1998 to determine if there is a range of resistance to European corn borer [Ostrinia nubilalis (Hübner)] (ECB) in commercially available processing sweet corn (Zea mays L.). Twelve processing corn cultivars were tested in 1997 and 18 cultivars in 1998. About 40 first instar larvae of colony-reared ECB were used to infest plants in both whorl and silking stages of growth. At harvest, plants infested at the whorl stage were evaluated for numbers of larvae and larval tunnels, and length of larval tunnels. Plants infested at the silking stage were evaluated for number of larvae per ear and were rated for ear damage using a 9-point scale. Resistance rankings among cultivars were consistent between years and between silk- and whorl-infested plants. We conclude that there is a substantial range of resistance already present in processing sweet corn cultivars, and that resistance is probably a combination of both exclusion and suppression of feeding. Our findings have two immediate uses: incorporation into existing IPM programs and incorporation of identifiable resistance bearing cultivars into a long-term breeding program for resistance to ECB in sweet corn.

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Thomas P. Kuhar, Michael P. Hoffmann, Lydia J. Stivers-Young, Susan B. Sterrett, and Michele Marini

Field cage experiments were conducted in Ithaca, N.Y. in 2001 to determine the yield effect of potato leafhopper (Empoasca fabae) infestations on early-stage beans (Phaseolus vulgaris). Yields of `Hystyle' snap beans and `Montcalm' dry kidney beans were significantly reduced when infested by potato leafhopper at the cotyledon, two-leaf, and four-leaf stages. For snap beans, no differences in yield response from potato leafhopper were observed among the three plant growth stages. For dry beans, there was a difference in yield response between cotyledon and four-leaf-stage plants. Dynamic economic injury levels for potato leafhopper on early-stage beans are suggested.

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Michael P. Hoffmann, Richard W. Robinson, Margaret M. Kyle, and Jonathan J. Kirkwyland

Seventy-six Cucurbita pepo L. cultivars and breeding lines were evaluated under field conditions for infestation levels and defoliation (leaf area consumed by beetles) by adult diabroticite beetles in 1992 and 1994. Striped and spotted cucumber beetles, Acalymma vittatum (F.) and Diabrotica undecimpunctata howardi Barber, respectively, were most common, but some western and northern corn rootworms, D. virgifera virgifera LeConte and D. barberi Smith and Lawrence, respectively, also were present. In general, pumpkin, delicata, acorn winter squash, scallop, and yellow straightneck summer squash types were the least infested and defoliated. Caserta/yellow, zucchini, caserta/zucchini, caserta, and precocious yellow straightneck types were the most infested and defoliated. The number of beetles per plant was correlated (r ≥ 0.72) with leaf defoliation and proportion of plants infested, indicating that beetle infestation is a good predictor of damage. The cultivars and breeding lines that were the least infested and defoliated can be used in breeding programs to develop desirable genotypes with reduced beetle preference. Conversely, those genotypes that were highly preferred have potential as trap crops for these beetle pests.

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James D. Frantz, Jeffrey Gardner, Michael P. Hoffmann, and Molly M. Jahn

A greenhouse screen for resistance to green peach aphid (GPA) [Myzus persicae (Sulzer)] was done using 50 pepper (Capsicum spp.) accessions. There were significant differences among accessions for damage rating, number of aphids per plant and number of aphids per leaf. Leaf pubescence, the basis of a reported nonpreference resistance mechanism to green peach aphid infestation, failed to protect pepper accessions from GPA colonization and damage. Sources of resistance and tolerance to cotton aphid [Aphis gossypi (Glover)] supported high levels of green peach aphid infestation and exhibited considerable damage. Although no accessions provided strong resistance to aphid colonization evident by significantly reduced numbers of aphids, several commercial varieties and sources of virus resistance exhibited strong tolerance to GPA, evident as reduced damage. Tolerant varieties could be an important component in integrated pest management of green peach aphid.

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James D. Frantz, Jeffrey Gardner, Michael P. Hoffmann, and Molly M. Jahn

A replicated greenhouse evaluation of a range of commercial and noncommercial (Capsicum spp.) accessions for resistance to european corn borer (ECB) [Ostrinia nubilalis (Hubner)] was conducted. Percentage of fruit damaged was observed among 29 accessions four weeks after plants were artificially infested with ECB egg masses. Small-fruited peppers generally showed lower levels of damage, while large-fruited peppers were the most susceptible. Genotypes with elongate fruit were less damaged than those with bell-shaped fruit. Resistance to fruit damage was also associated with increasing pungency level, with two notable exceptions. The pungent genotype `Large Red Thick Cayenne' was significantly more susceptible than many of the other pungent accessions tested. The relative susceptibility of this accession may be related to large fruit size. The nonpungent pepper `Corno di Toro' showed significantly lower percent fruit damage than other nonpungent peppers including `Banana Supreme' with roughly similar fruit size, ranking amidst highly pungent peppers such as `Red Scotch Bonnet'. These results confirm that resistance to ECB can be identified in nonpungent Capsicum genotypes and demonstrate that pungency is not always correlated with ECB damage. Reported sources of aphid resistance or tolerance showed good levels of ECB resistance, but interpretation of these results was confounded by the presence of pungency.

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Nita A. Davidson, L. Theodore Wilson, Michael P. Hoffmann, and Frank G. Zalom

Temperatures recorded by weather stations and within the canopy of tomato (Lycopersicon esculentum Mill.) crops were compared in fields near Davis, Calif., during Summer 1983 (60 days) and 1987 (50 days). For both years, the average maximum and minimum temperatures, daily temperature ranges, degree days per day, and total accumulated degree days were compared. In 1983, the mean maximum temperature at the weather station did not differ significantly from that in the canopy, but the mean minimum temperature at the weather station was significantly lower than that in the canopy. In 1987, the mean maximum temperature at the weather station was significantly higher than that in the canopy, but mean minimum temperatures did not differ significantly. Temperature ranges were significantly narrower for the weather station toward the end of the 1983 season, and significantly wider for the weather station at midseason 1987. Comparisons of degree days per day showed significant differences between means at the weather station and in the canopy in 1983, and among those at the weather station and the two degree day calculation methods used for temperatures recorded in the canopy. Total accumulated degree days based on temperature records at the weather station were lower than those in the canopy in 1983 but higher in 1987. In 1987, the single sine degree day calculation method overestimated degree days compared to the 2-hr triangulation method. The phenology of the tomato crop as predicted by weather station temperatures indicated that tomato maturation was underestimated in 1983 and overestimated in 1987. The rate of development for hypothetical populations of Heliothis zea (Boddie) and Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) within the tomato crop was again underestimated in 1983 and overestimated in 1987, as based on temperature data of the weather station.