THE CHINCH BUG IN RELATION TO ST. AUGUSTINE GRASS 



IMPORTANCE OF DAMAGE 



Thousands of dollars are spent each year for replanting the St. 

 Augustine grass which, in spots varying in size from a few square feet 

 to several acres, has been killed by the chinch bug. This insect is the 

 only serious enemy of St. Augustine grass. 

 However, the loss is not confined to direct 

 chinch -bug injury, but results also from the re- 

 placement of this grass by less desirable grasses, 

 which comes about because of the expense and 

 labor of continual replanting and the unsightly 

 appearance of the affected surface. In some 

 districts the planting of St. Augustine grass 

 has been practically abandoned, largely be- 

 cause of a general lack of knowledge regarding 

 effective control measures. 



WHERE AND WHEN INJURY OCCURS 



Chinch-bug injury occurs in all parts of 

 Florida, being somewhat more severe in the cen- 

 tral and southern portions of the peninsula. 

 Apparently little damage is done to St. Augus- 

 tine grass in the other Southern States, in Cuba, 

 or in Porto Rico. Lawns on high, dry, sandy, 

 or shell soils usually show damage first, prob- 

 ably because they do not retain moisture and are. therefore, least 

 able to withstand the strain of an attack. Injury may occur at any 

 time from May to November and is most evident during dry weather, 

 largely because such conditions favor the rapid multiplication of 

 the bugs, but partly because of the lowered vitality of the plants. 



Figure 2. — Chinch bug : 

 Adult female of the 

 short-winged form. 

 Magnified about 12 di- 

 ameters. (Hortonand 

 Satterthwait) 



MANNER OF INJURY 



Chinch-bug injury to St. Augustine grass is first 

 noticed in the dying out of the grass in small spots 

 which increase in size with more or less rapidity and 

 may finally cover a considerable area. On account of 

 the progressive nature of the injury it is sometimes 

 called " dieback." Several of these spots may start in 

 a lawn and gradually fuse. 



The type of injury of the chinch bugs and their 

 destructiveness are largely a result of their gregarious 

 habits of feeding. Many young and adult bugs collect 

 at the base of one plant, draining its juices until it 

 withers, and then leave it in a body for the nearest plant. The plants 

 so attacked turn from green to a sickly yellow and soon wither 

 and die. 



Weeds spring up where the grass has been, increasing the unsight- 

 liness of the affected surface, but often the St. Augustine grass will 

 gradually reoeeupy the ground if given sufficient time. The common 

 practice is to replant the grass, but unless the chinch bugs are first 

 materially reduced in numbers the new plants in their turn are likely 

 to be killed. 



Figure 3. — Eggs 

 of the chinch 

 hug. Magnified 

 about 450 di- 

 ameters. (Hor- 

 ton and Sat- 

 terthwait) 



