THE CHINCH BUG IN RELATION TO ST. AUGUSTINE GRASS 3 

 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 

 replacement 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 because 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 central and southern portions of the peninsula. 

 Apparently little damage is done to St. 

 Augustine grass in the other Southern States, 

 in Cuba, or in Puerto Rico. Lawns on high, 

 dry, sandy, or shell soils usually show damage 

 first, probably because they do not retain mois- 

 ture 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. 



MANNER OF INJURY 



Figure 2. — Chinch bug : 

 Adult female of the 

 short -winged for m . 

 Magnified about 12 di- 

 ameters. (Horton and 

 Satterthwait.) 



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 con- 

 siderable area. On account of the progres- 

 sive 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 reoccupy 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. 



