Bean Leaf Beetle Battle

Reports are coming in of bean leaf beetles being found in many early emerging fields as far north as Oxford and Brant Counties. This is much farther north than growers are used to at this time of year. Get out and scout your fields as soon as they emerge, especially if your soybean field is the first to come out in your area. Don't overestimate the damage they are doing. It does take a lot of beetles per plant to justify a spray. Seedling plants can take up to 30-40% defoliation, as long as there are not a lot of plants being clipped off. Seed, IP or food grain fields are most at risk. The threshold is 16 beetles per foot of row (4-5 beetles per plant) before the V3 stage or if extensive clipping is noticed. Once plants are in the V3 stage, the plants can usually outgrow the beetle feeding. New leaves come out making it even more difficult for the beetles to cause more than 30% defoliation to justify a spray. For more information on bean leaf beetle management, refer to last week's article in CropPest Ontario.

Related Links:

• Soybean Emergence = Risk of Bean Leaf Beetle Injury/CropPest - May 24, 2007

   

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