A study was conducted to evaluate 22 cowpea genotypes for antibiosis type of resistance to corn earworm in various cowpea genotypes grown in a replicated field trial. Crop resistance is one of the strategies which could be used for the management of corn earworm in cowpea (Vigna unguiculata L. Also, threshold levels for key pests need to be evaluated.Ĭorn earworm (Helicoverpa zea Boddie) is a potential pest of cowpea in the U.S.A. The minimum spray application needs to be integrated with other insect pest management practices such as time of planting and host crop resistance. The number of pod sucking bugs and corn earworm larvae was also significantly reduced in the spray treatments. It was concluded that one spray application at 5% podding could provide significant increase in the seed yield of cowpea and could abo reduce the percentage infestation of pod borers. However, in the first experiment which received spray application of endosulfan, the infestation percentage of insecticide treatment was similar to the control, probably due to lack of residual effect of endosufan. Also, there was a significant reduction in infestation of cowpea pod borers in the insecticide treatments compared with the control, especially in the second experiment which was sprayed with a mixture of insecticides (Cypermethrin + dimethoate). The results showed significant increase in the seed yield of cowpea in treatments which received the insecticide sprays. The sprays were started at 5% flowering and 5% podding stages, followed by second spray applications after 15 days. The number of sprays varied from one to two. Studies were conducted to evaluate the effect of minimum number and timing of insecticide sprays. There is no information on the number of minimum sprays for the management of cowpea pests in this region. Insect pests could cause significant losses in the seed yield if not controlled. The results indicate that introduction of cowpea in the Delmarva region could play an important role in replacing some of the areas currently being used for corn and soybean production, an important source of vegetable proteins to many ethnic groups in the area, play an important role as an alternative crop, improve soil fertility to sustain crop production, and also to serve as an insurance crop, especially during drought years in the Delmarva region.Ĭowpea is a potential crop in the Delaware, Maryland, and Virginia (Delmarva) peninsula region, U.S.A., which is a drought-prone area with predominantly sandy soils. Soils in the Delmarva region are sandy, prone to drought but support corn and soybean which are the major crops in the region.
Genotypes Quickpick Pinkeye and Elite were found to be early maturing and might escape the terminal drought. The highest biological yield was provided by genotypes Champion, White Acre and California Blackeye 5 making these genotypes good candidates to be used for green manuring or as cover crops in the region. Genotypes Colossus, Mississippi Silver and California Blackeye 5 gave significantly higher seed yields. Results showed significant differences in grain and biological yields of various genotypes. Cowpea genotypes were grown for two seasons and the parameters evaluated mostly included grain yield, biological yield, flowering and maturity dates. Field experiments were conducted to determine the possibility of growing cowpea as an alternative crop in the cropping system of the Delaware, Maryland and Virginia (Delmarva) region of the United States.
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