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Common stalk borers . These striped worms with a dark-purple band around the mid- 

 dle attack corn alongside fence rows, grass waterways, and ditch banks where they 

 have overwintered as eggs . When the worms outgrow the grass or weed stems or the 

 grass is mowed, the borers migrate into the adjacent corn. Sometimes, an attack 

 on young plants by the borers will kill the plant; other times, the plant may live 

 but will fail to produce an ear. Since these borers chew in the center of the 

 plant, the leaves that emerge are extremely ragged. 



Ordinarily, this pest is serious only along marginal areas such as fence rows, 

 waterways, and the like. But common stalk borers assume a new proportion as a 

 corn pest in no -till corn being grown in grass sod. These borers are very num- 

 erous throughout such fields. As the grass dies after being sprayed with a weed 

 killer, they concentrate on the corn. We have seen severe damage by this pest 

 for three years now. This year will probably be no exception. 



Control is on a catch-as-catch-can basis. A spray of carbaryl (Sevin) at 1 to 2 

 pounds per acre directed at the base of the plant may be helpful. As the borer 

 leaves one plant and crawls to another, it will contact the chemical. 



These pests are now appearing, so watch for wilting plants and check for this 

 insect. 



SMALL GRAINS 



Armyworms . This pest is still present in wheat, and a few severe infestations 

 have been reported this week. Examine fields snowing luxuriant growth. 



To determine the need for treatment, look first in the thick, lodged spots. Then 

 strike the plants vigorously to dislodge the worms. Count those on the ground 

 or in the debris between the rows, or in the cracks and crevices in the soil. If 

 you find many worms , make counts in several places in the field and figure the 

 average number per linear foot of row. If the average is six or more worms per 

 linear foot of row throughout the field, chemical control is justified. If you 

 do not find worms or only a f ew in the thick or lodged spots , treatment is not 

 necessary. 



After wheat is in the dough stage, loss of leaves is relatively unimportant. The 

 real damage from armyworms will occur if they begin to cut the wheat heads or 

 migrate to other, nearby crops. 



When using toxaphene, do not expect good control for about four days. Not only 

 is toxaphene a slow-acting toxicant, but 50 percent of the worms will not come 

 in contact with the spray for at least 48 hours. 



Of encouragement is the fact that wasp parasites of armyworms are beginning to 

 appear in numbers and may control many infestations. The clusters of small 

 white cocoons found in the ground in wheat fields are the pupal stage of this 

 parasite. The wasps will emerge from them and lay eggs in more armyworms. In 

 one field, about 25 percent of the armyworms had been parasitized this week. 



SOYBEANS 



Clover root curculios . This grey snout beetle often migrates from alfalfa and 

 clover fields when they are plowed. Tliese beetles concentrate on soybeans, 

 eating notches in the new leaves and gouging holes in the stems. Often, the 

 leaves are almost entirely consumed. A spray of malathion or carbaryl will 

 control this pest, if control is needed. 



