169 



Howard (F. K.). Nicotine Dust for Grape Leafhopper. — Calif. Cult., 

 Ivi, no. 21, 1921, pp. 671 & 678, 1 fig. (Abstract in Expt. Sta. 

 Record, Washington, D.C., xlv, no. 8, December 1921, p. 757.) 



Dusts containing as much as 10 per cent. Black-leaf 40 in various 

 combinations were used against the adults of the grape leaf-hopper 

 [Typhlocyba conies], but in all cases it was found that the insects were so 

 active as to avoid satisfactory contact with these materials. Where 

 the proper contact could be secured, dusts containing 5 per cent, or 

 more of Black-leaf 40 were found to kill the insect. 



It is concluded that a large percentage of the wingless nymphs can be 

 cheaply and effectively killed in this manner, and it is recommended that 

 the materials used should contain at least 5 per cent, of Black-leaf 40, 

 and that from 60 to 75 per cent, of sublimed sulphur be added to combat 

 mildew. The application should be made in such a manner that the 

 dust is directed upward into the vines, since the young occur on the 

 lower surfaces of the leaves. The young hoppers are said to have 

 commenced hatching on the 1st May in the Fresno district of California. 

 The application should be made when the majority of the insects 

 have hatched, and when as few as possible have reached the winged 

 stage. It is thought possible that in the worst infestations two dustings 

 may be necessary to destroy all the individuals of the first brood. 



IriE (G.) Las Plagas del Algodon en la Comarca Lagunera. [Cotton 

 Pests in the Laguna District.! — Rev. Agric, Mexico, vi, no. 9, 

 January 1922, pp. 504-513, IS^figs. 



The information in this paper concerning Platyedra {Pectinophora) 

 gossypiella (pink boll worm), which is the worst pest of cotton in the 

 Laguna District of Mexico, has previously been noticed [R.A.E., 

 A., ix, 461, 587]. Of less importance is Anthonomus grandis 

 (cotton bollworm), which, under normal conditions, can never be a 

 very severe pest in the district. It is endemic in the region and 

 increases in numbers towards the end of autumn. Serious damage 

 is caused by Aphis gossypii, which collects in numbers on the lower 

 surface of the leaves and at the tips of the branches, causing yellowing 

 and defoliation. Nicotine has proved the best remedy for this Aphid. 

 Tetranychus himaculatus webs the lower surfaces of the leaves and 

 causes defoliation by its punctures, and sometimes the death of the 

 plant. This mite increases rapidly, and when infestation is severe 

 it is best to destroy the focus of infestation and spray the surrounding 

 area with calcium bisulphide. The bug, Pentatoma ligata, is not 

 widely distributed. It causes withering of the bolls and a conse- 

 quent reduction in the crop. The caterpillars of Alabama argillacea 

 and Heliothis ohsoleta {armigera), do considerable damage, especially 

 in rainy seasons ; their control by means of arsenical dusts is 

 comparatively easy. 



C AXON I (L. A.). Dos Plagas del Algodon que no queremos en Puerto 



Rico. [Two Cotton Pests that are not wanted in Porto Rico.]— 

 P.R. Instdar Expt. Sta., Rio Piedras, Circ. 41, April 1921, 9 pp. 

 [Received 27th January' 1922.] 



The Porto Rico Department of Agriculture requests all cotton- 

 growers to co-operate in guarding against importing into the Island 

 any cotton seed proceeding from countries where Anthonomus grandis 

 (cotton boUworm) or Platyedra {Pectinophora) gossypiella (pink boll- 

 worm) occur [see, however, R.A.E., A, ix, 560]. 



(5980) Wt. ; 1,500 4/22 Harrow G. 75 M 



