176 



and the stoves lighted at 6 p.m., and at 1 a.m. the moths on the top 

 floor began to succmnb to the heat of 114° F ; at 10.30 p.m., the follow- 

 ing day, when the temperature had reached 120° F. on the third floor, 

 108° F. in one place and 120° F. in another, on the second floor, no 

 living insects could be seen. When the store was re-visited two weeks 

 later, there were no signs of the insects. Fumigation with carbon 

 bisulphide is recommended for the destruction of dry cereal pests. 

 Before fumigating, the buildings must be made as nearly air-tight as 

 possible ; 4 lbs. of carbon bisulphide should be used for every 1,000 cubic 

 feet of space and the operation performed at a temperature above 

 70° F. ; the quantity may be doubled for a severe infestation or where 

 the building cannot be sufflciently closed up. The fumigation should 

 last 36 hours and if the grain is not to be used for seed, may be ex- 

 tended to 48 hours. Small quantities of infested grain may easily 

 be treated by filling an ordinary coal-oil barrel, which will hold about 

 5 bushels of grain, and adding carbon bisulphide, 1 oz. to 100 lb. seed ; 

 this may be poured on the grain or placed in a shallow receptacle, the 

 barrel being closed up tightly, either with a special cap or with fine 

 sacks over which boards are placed with weights upon them. Exposure 

 to the gas should be for at least 36 hours. 



Watson (J. R.). Tomato Insects, Root-knot and " White-mold." — 



Florida Agric. Expf. Sta., Gainesville, Bull. no. 125, December 

 1914, pp. 57-78, 14 figs. 



CJiloridea (Heliothis) obsoleia (boll worm, or tomato fruit worm) is 

 the most serious pest of the tomato in Florida ; its favourite food- 

 plant is sweet maize, but it also attacks, among other plants, cotton, 

 green peas and beans. In Florida, there are three or more broods, 

 the winter generally being passed in the pupal stage, but occasionally 

 an adult hibernates. On the tomato, which is attacked mostly in 

 early spring, the eggs are laid on the leaves. The yomig larvae 

 soon migrate to the stems, into which they bore and as soon as the 

 young fruit are set, they mine inside them. While making their way 

 into another fruit, the larvae may be poisoned by any arsenical with 

 which the fruit is sprayed, especially when the first fruits are so small 

 that they are not able to eat their way inside. Applying arsenicals 

 quite early, when the first fruits are the size of marbles, is advised, 

 because by the time the fruit is ready to pick, the expansion due to 

 growth will have destroyed all signs of spray, even if there has been no 

 rain. Using lead arsenate at the rate of two or three pounds to 50 

 U.S. (41| Impl.) gallons of water, the chances of poisoning the 

 consumer, even if the fruit is sprayed only a day or so before picking 

 and is not washed before eating, are negligible. As, however, any 

 trace of the spray on the fruit at the time of marketing would 

 probably interfere with its sale, it is recommended that spraying be 

 discontinued 7 to 10 days before the first picking. If there is no rain, 

 the second spray should be given a week after the first, but should it 

 rain shortly after the first spraying it would be advisable to apply a 

 second spray within three or four days of the first. Even a single spray 

 will greatly reduce the percentage of infestation. In experiments 

 conducted by the author during tlie summer of 1914, the half-grown 

 fruits were sprayed once, and careful counts a week later showed that 



