4 CIRCULAR 51, U. S. DEPARTMENT OF AGRICULTURE 



PLANTS ATTACKED 



Iii the territory where chinch bug injury to St. Augustine grass 

 is severe no other cultivated plants are seriously attacked, although 

 the insect is known to feed on several wild and cultivated grasses. 



STAGES AND LIFE CYCLE 



Three general stages are recognized in the development of the 

 chinch bug, namely, the egg, the nymph, and the adult. 



Eggs are deposited on the St. Augustine grass at or near the points 

 where it comes in contact with the soil, or they may be scattered about 

 the plants in the soil. The eggs hatch into nymphs, in Florida dur- 

 ing the summer in from 9 to 13 days, the average period of the egg- 

 stage being 11 days. The nymphs require, on an average, 30 days to 

 reach maturity. They change color as already described and molt 

 four times before becoming adults. The time which elapses after 

 the adult stage is reached before the first eggs are laid ranges from 



5 to 13 days, the average being 8 days. Thus the average length of 

 the total life cycle is about 49 days. 



NUMBER OF GENERATIONS 



Since the average length of the chinch bug life cycle is 49 days, it 

 is possible that in Florida at ordinary temperatures there are five or 

 more generations a year. However, as the egg-laying periods extend 

 over a considerable time, the generations become badly mixed, and, 

 even in the spring, adults and all sizes of nymphs may be found 

 together. 



HIBERNATION 



Iii northern Florida the adult chinch bugs hibernate or become 

 dormant with the approach of cold weather. In the extreme southern 

 portion of the peninsula it is probable that the adults are active 

 during all but a few of the colder days of winter. Dry grass grad- 

 ually collects about the roots of St. Augustine grass, particularly in 

 the older lawns, affording ample shelter for the bugs' hibernation 

 and rendering it unnecessary for them to leave their feeding grounds. 

 This fact is confirmed by the knowledge that the spring infestation 

 often starts where the injury stopped the preceding year. Spring 

 infestation may sometimes also start around the bases of trees and 

 palms, indicating that hibernation has been accomplished in these 

 somewhat sheltered places. 



NATURAL ENEMIES OF THE CHINCH BUG 



In the district where St. Augustine grass is grown the natural 

 enemies of the chinch bug, such as insects, reptiles, and birds, have 

 little effect in controlling outbreaks of the pest. 



Probably because of the repugnant odor of the chinch bug, the 

 number and effectiveness of its enemies are not so great as with many 

 insect pests. Among the insects known to attack it are lady beetles, 

 ground beetles, lacewing flies, ants, and some of its near relatives 

 among the true bugs. 



