-  E-215 
—_ MONTHLY LETTER OF THE BUREAU OF ENTOMOLOGY 
UNITED STATES DEPARTMENT OF AGRICULTURE 


Number 88 sail Augudtey--1O2k 
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Agricul iture 
TRUCK-CROP INSECT INVESTIGATIONS 
LOA AN RE ET Sa OO 

Fr. H. Chittenden, Entomologist in Charge 
Neale F, Howard, in charge of research work on the Mexican bean beetle, 
reports that the damage by this species in the district around Birminghan, 
Ala., is again extremely serious, most of the Lima beans, garden beans, and 
field beans being already completely destroyed (August 9). The third generation 
of beetles has been completed, and indications ere that a fourth, and possibly 
a fifth generation will be secured bafore frost. At the present time, there is 
a considerable migration of adults, and observations and experiments on length 
of flight tend to show that considerable distances may be covered. 
In addition to food plants already reported, which include the various 
species of Phaseolus (garden and Lima beans), Vigna (cowpea), Dolichos (hyacinth 
bean), and Glycine (soy bean), a number of new hosts are reported, including 
velvet bean, alfalfa, AdZuki bean, and plants of the genus Desmodium. In the 
latter instance, injury is particularly severe. In a bean garden examined, 
a number of plants of beggar-weed were separated by a strip of cowpeas from 
several rows of badly infested Lima beans. The cowpeas were only slightly 
injured, while the beggar-weed was heavily infested, containing all stages of 
the beetle abundantly. Apparently an abundant and widely distributed wild 
host plant which insures the establishment of the beetle has thus been adopted. 
Studies of native natural enemies and the introduction of beneficial insects 
from other sections of the United States are receiving serious attention. 
The spotted ladybird (Megilla maculata) has been observed to feed extensively 
upon the eggs. A shipment of coccinellids from California has also been tested, 
and recently, through A. F. Burgess, 25 pairs of the predacious ground-beetle 
Calosoma syconhanta have been under observation. An egg parasite of Lema 
trilineata is also the subject of tests regarding the possibility of its trans- 
ference to the eggs of the bean beetle. 
Mr. Howard, accompanied by L. L. English, field assistant, recently 
visited the vicinity of Chattanooga, Tenn., for the purpose of making observations 
On bean-beetle infestation in that area. The infestation in that vicinity 
and in northern Georgia is light as compared with Birmingham conditions, and 
no serious damage has as yet been noted. This tends to substantiate the belief 
that this region has been infested much more recently than that around Birming- 
ham, Ala. 
Under the direction of H, H. Kimball, of the State Plant Board of 
Mississippi, 30 field men of that organization visited Tuscaloosa, Ala., 
July 27, for the purpose of observing and familiarizing themselves with the work 
on the Mexican bean beetle and with its characteristics, since the pest has 
not as yet been found in Mississippi. Mr. Howard gave a short informal talk 
on the beetie, its characteristic injury and its habits, and outlined the work 
