53 .VXXrAL KIM'OK TS OF I »1 il'A K T.M 1 :\ i' < M" A< ;KI( TI/rrKK. V.VM 
history. Tho more Mhuiidaiit and iniporlaiit jtarasitf, I\r]iihm(ln.<< sj)., has been 
found to occur in Arizoiui. Arkansas. Ivouisiana. Mississippi, and Soutli Carolina, 
and in 80 counties in Texas. .1. iniomoccru.s lias been bred from th'a liopiier 
cjrjrs onlj- from Arizona and Texas. An averaj;e of 25 percent of the ll.OO) 
tlea hopper ejj.^s in the stems of croton phmts collected in six States last year 
were parasitized. The information secured to date indicates that Ernthmelus 
passes the winter within the overwintering eggs of the Ilea hopper and also 
I)arasif i/.»'s the cltl's of other mirids. 
PINK BOLLWOKM 
The introduced parasites Microbracon Itrcvifoniis Wesm. and Krrristcs 
rohorator F. apparently did not become established in Texas or Mexico after 
liberations over a 3-year period. The latter species, however, appears to be 
established in Puerto Rico, and further breedini; and lil)erations of these si>ecies 
were discontinued. Recoveries of M. k Irk iKit rick i Wilk. and Chclonus hlackburni 
Cameron have been made near the points of liberation in Texas, Mexico, and 
Puerto liico. and althoui-'ii establishment is not certain, the prospect is encour- 
^ij,Mn^' and further liboratioi'.s will be made. In the Presidi(» Valley. Tex., the 
Hawaiian strain of M. niclJitor Say was recovered followinq: initial releases last 
season, but its present status is undetermined. 
Further studies of the native psirasites oc( urrinir in Mexico have shown that 
one species of Diptera and at least four species of Hymenoptera, and possibly 
others, attack the pink bollworm. These native parasites are becoming of 
increasing importance, although they do not exercise suflicient control to pre- 
vent heavy annual infestations and damage. Technique for laboratory rearing 
of Microbracon phiti/notae Cu.sli. and PcrifiieroUi rcllnlnris var. puuctaiictiJis 
Kieff. were developed, and small liberations were made to study the pos.sibility 
of increasing their effectiveness. The former species was found to breed on 
an undescribed lepidopteron which occurs abundantly on blue weed {Hcliauthus 
ciliaris). 
Three screened insect-proof field cages covering approximately 1 acre of land 
were completed and placed in use at Presidio, Tex., to prevent the movement of 
moths from surrounding fields from interfering with experiments to secure more 
definite information on the effect of cultural practices on the control of the 
pink bollworm. Additional tests with several (piick-maturing eastern varieties 
of cotton again demonstrated that the damage from the pink bollworm in heavily 
infested areas can be considerably reduced by the selection of proper varieties, 
and by cultural practices such as close spacing and controlled irrigation, which 
hasten maturity and reduce the late seasonal damage and the build-up of the 
fall population which goes into hibernation. Although no resistance to the 
pink bollworm was evident in the varieties of cotton tested and all of them 
became KHj perc(>nt infested, there were indications that the grade of the lint 
was not lov.-ered as much in the varieties with a high percentage of lint as in 
the varieties with a low percentage. In cage tests with cotton growing under 
controlled conditions, barium fiuosilicate du.st gave the greatest reduction in 
the number of worms per boll of any of the insecticides tested. Satisfactory 
control has not been secured with any of the materials tested, and further 
tests with this and other fluorine materials are in progress. 
Several species of malvaceous plants were found to be hosts of the pink 
bollworm in I'uerto llico, but only the seed pods of the two trees }fo)itr-inna 
spccim^is.sima and Thcsprftid pnpiiliira are considered important in providing a 
continuous supply of food for breeding during the closed season for cotton. It 
was definitely established that long-cycle larvae occur in Puerto Kico, the 
resting period of which may last for several months undi'r dry conditions but 
is m;it«rially shortened under favorabk» moisture conditions. These studies 
are of i)ractical importance in reducing the damage to cotton by proper adjust- 
ment of the jtlaiiting datc^s to the rainfall distribution, and the local autlu)rities 
have modified the regulations so as to i)rescribe uniform planting and closed 
seas^)ns for the entire island instead <>!' (lilVerent seasons for the northern and 
sotithern i)arts of the island. 
COTTON LEAF WORM 
The cotton l(:if worm made its ajipearance in scnithern Texas early in May 
UVMi and reached all cotton States except California before the end of the 
season. Although large (juantities of arsenical poisons were used to control it, 
considerable damage was <l<>nf in regions where it ai)peared early, ^^ome 
n-gions were not reached until after the croj) was mature, and the defoliation 
of the <(>llon jilants greatly rcdnred boll weevil i)oj)ulation to t>nter hibernation 
