

-2- 



Grape colaspis is damaging occasional fields of corn planted on a plow down of red clover, 

 according to late reports. These small white grubs chew off the root hairs. Row treat- 

 ments of aldrin or heptachlor do not provide adequate protection against this insect, but 

 broadcast treatments are effective. Affected plants are stunted and the leaves turn purp] 

 indicating a lack of phosphate due to the inability of the damaged roots to absorb a suf- 

 ficient amount. The grubs will mature and complete their feeding during the next two to 

 three weeks. Generally, plants will recover and produce a near-normal yield unless the 

 damage is extremely severe. 



CORN AND SOYBEAN INSECTS 



White grubs have been reported as numerous in a few fields now being plowed in the centra] 

 section. These are mainly fields in a continual corn-soybean rotation. The grubs are 

 generally large, indicating that this is the last year of their cycle. These large grubs 

 will finish feeding in mid to late June and will burrow down in the soil to form the rest- 

 ing (pupal) stage. Next year about this time, the adult June beetles will emerge and lay 

 eggs in soybean or sod fields to complete the cycle. 



If the field is to be planted to soybeans, a delay in planting to allow the grubs to finis 

 their feeding period will be helpful. If the beans have already been planted, nothing can 

 be done. 



Before planting corn, broadcast 2 pounds of actual aldrin or heptachlor per acre and disk 

 it in. After corn is up, it might help to spray 1 pound of actual aldrin or heptachlor 

 per acre. Direct the spray at the base of the plants. Cultivate immediately to throw 

 soil over the sprayed band. This will provide some help but will not be perfect. Rain 

 following treatment will improve control. Corn treated in the same manner should not be 

 used for ensilage or stover, but it may be used safely for grain. Do not make treatments 

 after July 1. Do not use aldrin or helptachlor on dairy farms. 



FORAGE INSECTS 



Alfalfa weevil populations are beginning to level off and decline as the larvae pupate. 

 Parasites take their toll, and adults lay fewer eggs. The problem area lies south of 

 Route 9. 



Watch the new growth of the second crop. If it does not green-up in 2 to 4 days after 

 cutting, and if worms are present, spray it promptly. When the second-crop growth is con- 

 siderable, apply an insecticide as soon as 25 percent or more of the terminals show no- 

 ticeable feeding. (This applies mainly to the southern third of the state.) Larvae of 

 the alfalfa weevil will be present and easily found for several weeks yet, but the peak 

 period for damage is over in most areas. 



For control of the alfalfa weevil larvae, farmers making their own applications should 

 use malathion or a commercially prepared malathion-methoxychlor or methoxychlor-diazinon 

 (Alfatox) mixture. Commercial applicators can use the above materials or one of the 

 more-toxic insecticides like methyl parathion or azinphosmethyl (Guthion) . Be sure to 

 follow label directions for dosages, harvest limitations, and precautions when using in- 

 secticides . 



Lesser clover- leaf weevil larvae can be found feeding behind leaf sheaths and along the 

 stems of red clover. The larvae are gray to dirty-green, legless worms with a black 

 head. They can usually be found in a dirty groove on the stem or in a tunnel inside the 

 stem behind a leaf sheath, or in terminal buds. Infested plants are often stunted, and 

 stems and leaves may wilt and die. The blooms dry-up and turn brown prematurely. No 

 practical control measures are known. 



