334 



AsHwoRTH (J. T.) & Brixton (W. E.). Report of Gipsy Moth Work. 

 Season of 1920-1921. — Conn. Agric. Expt. Sta., New Haven, 

 Bull. 234, 1922, pp. 132-145, 1 fig., 1 plate. 



The policy pursued in former years with regard to the suppression 

 of gipsy moth [Porthetria dispar] [R.A.E.. A, ix, 292] has been 

 continued with further success. Two new infestations were found, 

 but many previously infested areas were free. Details of the work 

 are given, arranged under the towns. No less than 1,598,775 individuals 

 of the egg-parasite, Schediiis kiivanae, How., were liberated in the 

 north-eastern part of the State. 



Watch is still being kept for the brown-tail moth [Nygniia 

 phaeorrhoea], but as it is very scarce, remedial measures are at present 

 unnecessary in Connecticut. 



Garman (P.). Notes on the European Red Mite, Paratetr any elms 



pilosus, C. & F. — Conn. Agric. Expt. Sta., Neia Haven, Bull. 



234, 1922, pp. 146-152. 

 As a result of the experiments with various insecticides for the 

 destruction of the eggs of Paratetranychus pilosus, it is evident that 

 miscible oils are valuable ovicides, but if used in excessive quantities 

 they may injure the apple trees, especially the trunk and larger limbs. 

 In Connecticut, miscible oil should be applied as a dormant spray before 

 the buds open in March or early April. If a delayed dormant spray 

 of lime-sulphur is used, it should be applied as late as possible, as it 

 kills the young mites after hatching [cf. R. A.E., A, ix, 293]. 



Garman (P.). The Violet Gall Midge, Phytophaga violicola (Coquillett). 



— Conn. Agric. Expt. Sta., New Haven, Bull. 234, 1922, pp. 

 152-156, 1 fig., 1 plate. 



Contarinia [Phytophaga) violicola became so abundant during 1920 

 in certain greenhouses in Connecticut that continual hand-picking 

 had to be adopted. The yearly loss from this midge has been estimated 

 at about ^200. Intermittent fumigation with hydrocyanic acid gas 

 and dusting with lime have not proved successful. The eggs are laid 

 in the curled portion of the leaves, and under laboratory conditions 

 they hatch in from four to six days. Soon after the eggs hatch the 

 leaves have a deformed appearance. The larvae remain in the curled 

 portion until ready for pupation, for which purpose they enter the 

 soil to a depth of about one millimetre. The pupal stage lasts about 

 two weeks. The total life-cycle from egg to adult varied from 33 to 37 

 days. These records were taken during October and November 1920, 

 the temperature being much lower than is usually maintained in com- 

 mercial greenhouses during the summer ; later observations indicate 

 the possibility of a shorter life-cycle, probably about three weeks. 



Applications of insect powder and dry lime to the soil failed to kill 

 the larvae or pupae. Systematic fumigation with hydrocyanic acid 

 gas appears to be the most satisfactory remedial measure at present, 

 but it must be repeated every other night, as only the adults are killed, 

 the pupae in the soil not being affected. Sodium cyanide may be used 

 for fumigation, but the dose should not be reduced below 1 oz. per 

 1,000 cubic feet ; in leaky greenhouses 1-2 oz. v/ill be required to 

 kill the midge. Violets can withstand a heavier dosage than other 

 plants, but when apphnng an increased amount the house should 

 not be left closed over night. 



