94 



PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



INSECTS OF THE COTTON STAINER FAMILY (PYRIIHOCORID^) 

 INJURIOUS TO COTTON. 



THE BORDERED PLANT-BUG. 



(Largus sucdnctus L.) . 



This insect (PL I, fig. 7; text figs. 24, 25) has been briefly mentioned 

 as a minor cotton pest by Professor Sanderson,^ who has indicated 

 the more important pubhshed references. The insect is generally dis- 

 tributed throughout the Southern States. Lintner has recorded its 

 attack on ripening peaches at San Antonio, Tex., in 1885, but this 

 apparently indicated nothing more than an occasional depredation. 

 The insect has been observed by the present writer to breed in enor- 

 mous numbers in alfalfa fields at Tlahuahlo, Durango, Mexico. It 

 has also been found in certain regions in Texas breeding on a weed, 

 Solanum torreyi, and on mesquite, but in each case only when growing 

 in the vicinity of cotton fields. Eggs are deposited in trash in masses 



averaging, in four instances, 180 eggs 

 each, and ranging from 108 to 215.^ 

 The eggs -hatch in about ten days at 

 an average daily mean temperature of 

 74° F. while about twice that time is 

 necessary when the temperature is 10 

 degrees lower. The damage to cotton 

 bolls by the bordered plant-bug is the 

 same as that caused by the Pentatomid 

 and Coreid bugs heretofore discussed. 

 Their preference for the cotton boll is 

 not as strongly marked, however, adults 

 and nymphs being much more fre- 

 quently found feeding on the outside of cotton squares at the base of 

 the bracts. The writer knows of no instance of this bug occurring in 

 cotton fields in numbers sufficient to cause by itself noticeable dam- 

 age except as observed in a few fields in Mason and Llano counties, 

 Texas, in 1905. In all cases referred to, the mesquite and the sola- 

 naceous weed mentioned above were evidently the chief breeding 

 places and as a rule only near-by cotton plants were damaged. The 

 newly-hatched nymphs have a dark brownish head and thorax, and 

 reddish abdomen. Later nymphal stages are characterized by a 

 greenish or bluish-black color with red markings. 



a Bul. 57, Bur. Ent., U. S. Dept. Agr., p. 46, 1906. 



& Professor Sanderson's record of 215 eggs in a mass is the maximum number referred 

 to above. 



Fig. 24.— The bordered plant-bug (Largus 

 sxicdnctus): Nymph, first instar. Enlarged 

 21 diameters. (Original.) 



