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Legume Virus Project

A resource for managing aphid-vectored viruses in cool season legumes

A. Seed Treatment (Peas)

We have conducted experiments during two seasons to compare Gaucho and Cruiser at a range of seed treatment rates for their ability to limit spread of BLRV and PEMV in pea. In summary, in 2010 only Gaucho appeared to be efficacious and only at a relatively high rate (1.6 to 3.2 oz per cwt). This treatment rate would be relatively expensive compared to foliar sprays of dimethoate, which were just as effective at slowing virus spread. Click here to view the seed treatment calculator.


B. Early Spray (Peas)

The severity of virus disease symptoms depends upon the timing of inoculation. Plants infected soon after emergence are more severely affected than plants infected later on. We have measured this effect for PEMV and BLRV in pea. In summary, if pea plants remain free of infection until 24 days after emergence, injury will be negligible. Injury before 10 days is expected to be severe. To see the data from this study, click here (Data). The effects of PEMV and BLRV are similar. With this information we are developing a calculator to help producers decide on insecticidal sprays for aphids early in the growing season. Click here to view the insecticidal spray calculator. This year (2011) and in 2012 we are conducting similar experiments designed to provide support in lentil.


C. Late Spray (Peas)

Based on our work, we have developed the following EIL for pea aphids as direct pests of dry peas. EIL represents the NUMBER OF APHIDS PER PLANT at which it is economically feasible to spray insecticides.

Economic Injury Level (EIL): the break-even pest density at which the cost of pest control (total cost to purchase & apply insecticide) is exactly equal to the benefits of pest control, where benefits are the value of preventable crop loss. Click here to view the pea EIL calculator.


D. Late Spray (Lentils)

Based on our work, we have developed the following EIL for pea aphids as direct pests of lentils. EIL represents the NUMBER OF APHIDS PER PLANT at which it is economically feasible to spray insecticides.

Economic Injury Level (EIL): the break-even pest density at which the cost of pest control (total cost to purchase & apply insecticide) is exactly equal to the benefits of pest control, where benefits are the value of preventable crop loss. Click here to view the lentil EIL calculator.


E. Aphid Sampling (Peas)

Based on our work, we have developed the following BINOMIAL SEQUENTIAL SAMPLING PLAN for pea aphids on dry peas. This plan was designed to quickly designate a pea aphid infestation as economic or non-economic. Click here to view the Binomial Sequential Sampling Plan.