tissues and sucking out the juices. On 

 cotton, they attack the tender terminal 

 growth, squares, flowers, and young 

 bolls. Injured squares and small bolls 

 usually drop. Injured bolls that do 

 not drop may open abnormally and 

 produce inferior lint that clings to the 

 warty carpels that result from lygus 

 feeding. 



Lygus damage reduces the yield; it 

 causes the lint to be spotted and lower 

 in grade. Injured plants develop ab- 

 normally; they become tall and whip- 

 like, and have fewer fruiting branches. 



USING INSECTICIDE 



When a damaging infestation of 

 lygus bugs is present on cotton, the 



BN-13921-X 



Lygus eggs in stem of cotton plant. 



only way to control it is by applying 

 insecticide. Two applications usually 

 give satisfactory control; occasionally, 

 three may be required. 



WHEN TO APPLY 



The Extension Service in each cot- 

 ton-producing State issues an annual 

 guide for controlling cotton insects. 

 Start your insecticide applications 

 when infestation reaches the level spe- 

 cified in your State guide. You can 

 obtain a copy from your county agri- 

 cultural agent or State agricultural 

 college. 



To determine the infestation level, 

 make a sweep count at each of four or 

 more locations in a cottonfield. You 

 can accomplish this by making 50 or 

 100 passes with a sweep net through 

 the tops of plants in 1 row in each loca- 

 tion, holding the net so its lower edge 

 slightly precedes its upper edge. Count 

 the number of lygus bugs collected in 

 the net, including the nymphs. Make 

 the sweepings at 5- to 7-day intervals, 

 beginning when squares start to develop 

 on the plants and continuing until early 

 September. When you know the num- 

 ber of lygus bugs a sweeping has col- 

 lected, you can refer to your State guide 

 to learn if it is time to apply insecticide. 



Another method of determining the 

 level of infestation is to walk diagon- 

 ally across the field and examine 3 or 

 4 inches at the top of the main-stem 

 terminals of 100 cotton plants, and 

 count the lygus bugs, both adults and 

 nymphs. These examinations should 

 be made at the same intervals and over 

 the same period as the sweep-count ex- 

 aminations. 



