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what kind of damage is caused by corn rootworms, the most important
economic insect pest of corn in illinois?
1. Larvae-chew on and tunnel in roots
2. adults-feed on and cut silks at ear tip
-reduce kernal pollination
What are the economic thresholds when scouting for corn rootworm
beetles?
1. when the silks are green, if silks are clipped within 1/2 inch of the tip of the
ear.
2. from late july to late august
a. in soybeans: 1.5 beetles per unbaited pherocon am trap per day
b. in continuous corn: 2 beetles per unbaited pherocon am trap per day
what kind of damage does black cutworm larvae do to corn seedlings?
1. chew small pinholes in corn leaves
2. cut plants off at or below soil surface
3. growing point could be destroyed
, What type of field factors increase the potential for black cutworm
damage to develop and why?
1. crop debris
2. winter annual weeds
3. late planted
what is the recommended methods for managing black cutworms in illinois?
1. scouting during plant emergence
2. control by using rotary hoe or cultivating on dry soil
3. rescue treatment when necessary
what type of damage does larval european corn borer cause?
1. tunnel inside plant and disrupt the flow of water nutrients to the ear
2. 2nd gen-lay eggs on lower side ear leaf
what type of damage does corn leaf aphid cause?
honeydew coats the tassel and possible the silks reducing pollination
describe wireworms and their damage
1. apperance:larvae are yellow to reddish-brown, hard shelled and wire like
2. damage: tunnel into seeds and seedlings below soil level