462 



LoFTiM (U. C). Apuntes sobre la Vida del Gusano rosado. [Notes on 

 the Life-history of Platyedra gossxpiclla.] — Rev. Agric, San 

 Jacinto, D.F., Mexico, v, no. 1, 1st September 1919, pp. 68-69. 

 [Received 25th July 1921.] 



A study has been made of keeping larvae of the pink boUworm of 

 cotton [Platyedra gossypiella] under various conditions during the 

 winter. It was found that no larvae remained alive after 24th April 

 in the bolls buried in moist ground, about 6 in. deep, while 10 per cent, 

 of those buried in dry ground survived until 4th June. Of those 

 left in the bolls above-ground, 45 per cent, remained alive. Burying 

 the stubble and irrigating the soil is, therefore, a sure method of 

 destroying the bollworms, and ploughing in the autumn also largely 

 reduces their numbers. Of larvae kept in the laboratory and examined 

 up to the 30th June, 3-3 per cent, of those kept in a meteorological 

 case in the open air had already hatched, 9 • 2 per cent, of those enclosed 

 in the double seed in which they were found, and 35-8 per cent, of 

 those taken out of the seed and enclosed in a glass case with a little 

 cotton. 



Cotton began to bloom on 17th May, and from that date onward 

 infestation increased irregularly during the month, the percentage of 

 infestation decreasing owing to the rapid appearance of the blossoms. 

 During the last days of June, the infestation notably increased, probably 

 owing to the appearance of larvae of the second generation. The 

 life-history under Mexican conditions was as follows : adult life before 

 oviposition, 2-8 days ; oviposition period, 4-8 days ; larval period, 

 10-17 days ; pupal period, 10-17 days ; or 23-33 days [sic], with an 

 average of 30 days for the whole life-cycle. The second generation 

 begins to appear during the last days of June, but from this date 

 onwards the broods are so intermingled that it is almost impossible 

 to distinguish them. 



Experiments showed that larvae separated from the bolls and sub- 

 merged survived for 48 hours, while those in submerged bolls survived 

 for 7 or 8 days ; there is, therefore, a danger of the larvae spreading 

 greatly during the irrigation period. Carbon bisulphide at the rate 

 of 1 lb. per 80 cu. ft. has given very good results in disinfection of the 

 seed. It penetrates a mass of seed to a depth of 5 ft., while hydro- 

 cj^anic acid gas will not penetrate more than a few inches into the mass. 



Ramirez (R.). Plagas de algunos Arboles Frutales. [Pests of certain 

 Fruit-trees.] — Rev. Agric, San Jacinto, D.F., Mexico, vi, no. 1, 

 May 1921, p. 43. 



Aspidiotus perniciosus (.San Jose scale) is recorded from the Federal 

 District of Mexico as a serious pest of chabacanos (Mexican apricots), 

 peach, plum, pear, and apple trees. A fungus of the genus Sporo- 

 trichum develops on the scales, but has not been found actually within 

 the body of the insect. The Acarine, Tetranychus sexmaailatits, 

 attacks apricots and apple trees. 



UnParasito de la Cana de Azucar, y un Inseeto destructor de las Hojas 

 del Chile. [A Parasite of Sugar-cane and an Insect destructive 

 to the Leaves of Chili.] — Rev. Agric, San Jacinto, D.F., Mexico, 

 vi, no. 1, May 1921, p. 47. 



Pseudococcus {Dactylopius) sacchari is reported on sugar-cane in 

 Mexico. Irrigation with paraffin and gasolene, or water containing 



