May 17, 1918] 



SCIENCE 



491 



bring them to the attention of both entomolo- 

 gists and pathologists who might be inter- 

 ested. 



Kernel spot has been reported by Rand* as a 

 coaumunicable disease. The same author iso- 

 lated a fungus which he recorded as the causa- 

 tive agent, and described it as a new species 

 (Coniothyrium caryogenum Rand). Other- 

 wise little or nothing has been published on 

 the disease. As the name implies, the disease 

 affects only the kernel of the pecan and its 

 presence can only be detected by removing the 

 shell. The spot on the kernel is irregular in 

 outline, dark brow^l or black in color and 

 usually somewhat sxmken. It varies from 

 one eighth to one half inch in diameter. 

 ■^Tien the kernel is cut the brown area is foimd 

 to extend into the meat to a depth of perhaps 

 one eighth of an inch. The affected spot is 

 bitter and imparts a bitter flavor to the rest of 

 the meat. 



The disease appears to be of general occur- 

 rence throughout the pecan belt, though ordi- 

 narily only a small percentage of the nuts are 

 attacked. Occasionally, however, as in 1916, 

 it becomes of very serious economic import- 

 ance, causing the loss of thousands of dollars 

 to the growers. 



The green soldier bug, Nezara viridula 

 (Linn.), is present throughout middle and 

 southern Georgia, being of common occurrence 

 every year and occasionally, as in 1916, be- 

 coming exceedingly numerous. The bug ap- 

 pears to attack cow peas in preference to all 

 other plants, either cultivated or wild, when 

 these are available. In the fall, when the pea 

 vines begin to dry up, the bugs leave them and 

 gather on any other plants or trees which they 

 may find in the vicinity. 



A very common practise among pecan grow- 

 ers is to sow peas in the groves during the 

 early summer, the vines to be turned imder, 

 later, as a soiling crop. As a result, when the 

 vines begin to dry up, usually in September 

 or early October, the bugs leave them and col- 

 lect on the pecans. 



It was noticed, during 1916, that there oc- 



1 Band, F. V., Jour, of Agr. Ees., Vol. 1 (1914), 

 No. 4, pp. 330-334. 



curred both a severe infestation of Nezara 

 viridula and a severe outbreak of kernel spot. 

 While it was entirely possible that this was a 

 mere coincidence several growers noticed it, 

 together with the fact that the disease ap- 

 peared to be serious only in the groves in 

 which cow peas had been sown. Moreover, in 

 at least one case, bugs were observed feeding 

 on the nuts. 



As a result, during the past season prelimi- 

 nary experiments were conducted in which 

 specimens of Nezara viridula, taken on cow 

 peas, were confined on pecan nuts. The bugs 

 fed on the green nuts, living on them for as 

 much as a month, in three cases. Examina- 

 tions made after the nuts had fully ripened 

 showed that every nut in the several cages was 

 severel.v infested with kernel spot, as many as 

 five distinct spots occurring on a single ker- 

 nel. Of several hundred nuts from the same 

 tree, not confined in cages, only two or three 

 had sjKitted kernels. 



It has not been possible, thus far, to deter- 

 mine whether the fungus, Coniothyrium caryo- 

 genum, is present in the spotted areas, or not. 

 In any case the data obtained are strongly 

 indicative of the fact that Nezara viridula is 

 an important agent in either the actual pro- 

 duction or the dissemination of this disease. 

 This is of particular interest since it is 

 another of the observations, becoming more 

 and more frequent during recent years, on the 

 economic importance of a large group of in- 

 sects (several families of the Heteroptcra and 

 the Cicadellidffi and Aphididae among the 

 Homoptera). Formerly these insects were re- 

 corded as injuring vegetation only when 

 abundant, through the purely mechanical proc- 

 ess of removing sap from the tissues. Of late, 

 however, we are beginning to realize that 

 many of them are of far greater importance 

 than had been realized, both as the primary 

 causative agents of specific plant maladies and 

 as vectors and intermediaries in the dissemi- 

 nation of other specific maladies of bacterial 

 or fungoid origin. 



William F. Turner 



Georgia State Board or Entomoloot, 



TUOMASVILLE, Ga. 



