660 EXPERIMENT STATION RECOBD. fVol. 87 



been more abundant than usual during the spring of 1916, it being especially 

 so on the California black-eyed variety of cowpeas. A June bug (Aiiomala 

 marginata) was especially abundant in June. The twig girdler {Oncideres 

 cingulattis) was the cause of several complaints from the lower east coast 

 where it attacked "Australian pines." 



Undesirable insect immigration into New Jersey, H. B. Weiss {Canad. 

 Ent., 49 (1917), No. 9, pp. 293-298, pi. /).— The author calls attention to the 

 fact that fully one-half of the principal injurious hexapods in the United States 

 have been introduced from foreign countries and that the injuries inflicted by 

 them have been enormous. Mention is made of the introduction into New Jer- 

 sey of the mole cricket GryUotalpa gryllotalpa from Holland (E. S. R., 34, p. 

 653), the large cockroach Blaherus discoidalis from South America (E. S. R., 37. 

 p. 255), Stephanitis pyrioides from Japan, and Cholus lorbeaii from Colombia. 



Fumigation of greenhouses, E. N. Coby {Maryland Sta. Bui. 205 (1917), pp. 

 263-284). — This bulletin is based upon fumigation experiments conducted with 

 the view of ascertaining the effect of certain doses of hydrocyanic-acid gas on 

 insects and plants when certain factors are known, including moisture and 

 temperature, meteorological conditions, time (day or night), and length of 

 exposure. The investigations were largely limited to the determination of 

 effective dosage for certain insects under normal conditions, but little work 

 having been done with one factor constant and others variable in order to 

 ascertain the effect of the variables, which, it is pointed out, is a very important 

 phase of fumigation. 



The conclusions drawn from the work carried on are as follows: "Fumiga- 

 tion in the presence of daylight Is likely to result in injury to the plants if a 

 sufficient dose is use<l to control tlie ordinary insects. . . . Overnight fumi- 

 gation is recommended because (1) fumigation in late afternoon for a short 

 period is impractical in winter, since ventilation after nightfall is likely to 

 result in chilled or frozen plants; (2) long exposure at night does not give as 

 much injury as a short exposure during the day. 



" Definite doses under optimum conditions of moisture and temperature for 

 different horticultural varieties of plants can be recommended. Definite doses, 

 under the normal greenhouse conditions, that will kill certain species of insects 

 are recommended. Slight reductions in the doses may be effected by increasing 

 the temperature up to a maximum of 70° F. without danger of injury to the 

 plants if the moisture is kept at or below 50 per cent .saturation. High moisture 

 is decidedly an important factor as far as injury to the plant is concerned. 

 High moisture will increase the mortality If the dose is below the optimum for 

 the insect involved. 



" High temperature will increase the mortality if the dose is below the opti- 

 mum for the insect involved. Plants that are normally grown under warm 

 conditions, such as ' stove plants,' will not be injured by fumigations in a tem- 

 perature that would injure bedding plants and plants grown for cut flowers. 

 Plants other than ' stove plants ' .should be fumigated if possible with the 

 optimum dose for the insect involved, at a night temperature at or below 50° 

 and with the atmosphere about half saturated." 



In an appended table the author gives the maximum .safe dose for various 

 plants under normal greenhouse conditions. 



A neglected factor in the use of nicotin sulphate as a spray, W. Moore 

 and S. A. Gkaham (U. S. Dept. Agr., Jotir. Agr. Research, 10 (1917), No. 1. 

 pp. 47-50). — Illness caused by the consumption of greenhouse lettuce that had 

 been sprayed with nicotin sulphate led to the studies at the Minnesota BJx- 

 periment Station here reported- 



