Testing the Efficacy of Three Insecticides to Control European Corn Borer Ostrinia Nubilalis in Potatoes

Project code: MU03-ENT6

Project Lead

Christine Noronha - Agriculture and Agri-Food Canada.

Objective

To test the efficacy of the products Avaunt® and novaluron® for control of larvae and/or eggs of European Corn Borer, an emerging pest of potato

Summary of Results

Field and laboratory studies were conducted to test the efficacy of foliar applications of three reduced risk insecticides, Avaunt®, Success® and Novaluron® in controlling the European corn borer in potatoes in 2004, 2005 and 2006 at Harrington farms in PEI, and the Potato Research Centre in New Brunswick. Field studies in 2004 and 2005 tested the efficacy of two rates of each insecticide sprayed twice over the summer. Results show that all three insecticides gave significant control of the European corn borer in potatoes when compared to the control. Percent protection ranged from 70-80%. No significant differences were found in the yields in 2004 however, in 2005 significantly fewer cull potatoes were found in both Novaluron® treatments. In 2006 it was found that while all treatments were effective in reducing damage from ECB populations, two applications of Avaunt® and Novaluron® gave significantly better control than one application, and also resulted in fewer culls.

In all three years Novaluron® was applied at the egg stage whereas Avaunt® and Success® were applied at the blackhead stage, just before egg hatch. A significant reduction in larval damage in the Novaluron® treatment indicates that this insecticide may have ovicidal properties and could be used earlier in the season as soon as eggs are detected. Laboratory studies to determine topical, residual and ovicidal activity were conducted at the Potato Research Centre in New Brunswick in 2004, 2005, and 2006. All three reduced risk insecticides tested were toxic when sprayed on European corn borer neonates. Success® was the fastest acting insecticide of the three. Small concentrations of Success®, below the recommended field application, were sufficient to obtain near 100% control of neonate European corn borer within 24 h after the larvae had been sprayed.

With Avaunt®, concentrations above those recommended for European corn borer field control were required to obtain near 100% control within 24 h; lower concentrations provided excellent control of neonate larvae over time. With Novaluron® a prolongation of the neonate stage occurred which is characteristic of insect growth regulators. When applied to the eggs an average 80% reduction in hatching of European corn borer eggs was observed with Novaluron® or Success® and the 60% reduction with Avaunt®. Novaluron® applied two days prior to black head stage showed that it is also effective against European corn borer at egg hatch. Results suggest that the upper end of the recommended range of application for Novaluron® will be preferable to improve the ovicidal property and accelerate the topical activity. Laboratory studies show that ovicidal properties of Success®, Avaunt® and Novaluron® are potent.

Results from this three year study show that three reduced risk insecticides can effectively control European corn borer in potatoes. The ovicidal activities of these chemicals will give growers a longer window of opportunity to control this pest, as they will not have to wait until the black head stage to apply an insecticide. This will provide more flexibility to deal with inclement weather which in turn should enhance European corn borer management programs.

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