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Development of an IPM system for the Mexican bean beetle (Epilachna varivestis Mulsant) as a pest of dry bean (Phaseolus vulgaris L.)
Abstract
During 1994 to 1996, studies were conducted in western Nebraska, to develop a pest management program for Mexican bean beetle (Epilachna varivestis Mulsant) in dry bean (Phaseolus vulgaris L.) based on egg mass sampling. A sampling survey to describe the spatial and probability distributions of egg masses produced a data set of 12,290 egg mass samples from four fields over two years. Semivariograms showed no sign of aggregation, even though the presence of macroscale trends indicated that Mexican bean beetle egg densities may be greater in areas of the field near edges adjacent to beetle overwintering sites. Egg masses had a negative binomial distribution. Life tables were developed by following known Mexican bean beetle cohorts (egg masses) in three fields in each of two years. High mortality occurred in the egg and first two larval stages. Egg mortality was related to drought-stressed bean plants, because stressed plants turn over their leaves and expose eggs to sunlight. The cumulative mortality ranged from 92.07% to 95.82%, in 1995 and from 60.89% to 75.6% in 1996. No parasitized larvae were observed in the study fields or those held for parasitism tests. Yield-loss relationships for Mexican bean beetle on dry bean were determined in a third study. Results from a series of experiments were combined with data from the other two studies to develop economic injury levels (EILs) and economic thresholds (ETs) and a sequential sampling program for Mexican bean beetle. The EILs calculated in larvae/row-m were converted to egg masses/row-m and adjusted to reflect the average survivorship to the adult stage. Because sampling is based on egg masses, growers can make management decisions and take management actions before significant injury will occur. An interactive spreadsheet was developed to calculate Mexican bean beetle EILs, ETs, and sequential sampling plans. The spreadsheet allows users to input economic and other data specific to their situation. The pest management tools presented in this work should provide a useful model for management programs for other insects pests in other systems.
Subject Area
Entomology|Biostatistics|Ecology
Recommended Citation
Barrigossi, Jose Alexandre Freitas, "Development of an IPM system for the Mexican bean beetle (Epilachna varivestis Mulsant) as a pest of dry bean (Phaseolus vulgaris L.)" (1997). ETD collection for University of Nebraska-Lincoln. AAI9805497.
https://digitalcommons.unl.edu/dissertations/AAI9805497