12 



BULLETIN 1102, U. S. DEPARTMENT OF AGRICULTUEE. 



each year. Most southern soils are naturally deficient in organic 

 matter, and unless supplied by means of growing cover crops for 

 green manuring each year the trees will soon suffer. 



The cowpea for many years has been the most popular cover crop 

 with pecan growers. It is an easily cultivated legume and adds a 

 large quantity of organic matter to the soil when plowed under. 

 However, it has been observed by the writer, as well as by several 

 growers, and also reported by Turner, that kernel-spot is almost 

 always found more abundantly in orchards planted to cowpeas. This 

 indicates that cowpeas may have to be discarded as a cover crop for 

 pecan orchards and some other luxuriant-growing legume substi- 

 tuted. It appears at present that velvet beans, preferably the bunch 

 variety, will largely take the place of cowpeas in bearing orchards. 

 The velvet bean is a legume, a rank grower, and the writer's obser- 

 vations as well as other available information indicate that it is 

 not a favored host for the stinkbugs. Kudzu and lespedeza are also 

 possible substitutes for cowpeas as summer cover crops in pecan 

 orchards. 



The writer made a preliminary investigation during the pecan 

 harvest during the season of 1921, attempting to learn in what sec- 

 tion of the tree kernel-spot is most abundant. About 150 nuts were 

 collected from each of five large Frotscher trees averaging from 30 

 to 40 feet high. The nuts were kept separate from the lower third, 

 middle third, and upper third of the trees. The nuts were cracked 

 and the kernels carefully examined for kernel-spot. Table 3 gives 

 the results. 



Table .3. — Sections of pecan trees in ivJiich kernel-spot is most abundant. 



Tree. 



Affected third (per cent). 



Lower. 



Middle. 



Upper. 



No. 1 



54 



61.2 

 49.9 

 92 



47 



46.6 

 18.2 

 19.8 

 68.1 

 



24 



No. 2 



17 



No.3 ... .... 



7.6 



No. 4 



69.6 



No.o 



2 







Average 



60.2 1 29.8 



24 











These results indicate that while the bugs are able to fly to the 

 tops of comparatively high trees, they do most of their feeding on 

 the lower limbs. The evidence procured in this study is not intended 

 to be conclusive, but suggests that in case the growers have an abun- 

 dance of kernel-spot they could possibly save a portion of their crop 

 by first harvesting the lower part of their trees, keeping these nuts 

 separate and cracking at home or selling to a cracking establishment, 

 thus eliminating what may be a total loss. 



