or>9 



the chief factor in conveying cotton boll disease from these plants to 

 cotton, where it is spread from plant to plant by the cotton stainers 

 {Dysdercus). Experiments show that both N. viridula and the tomato 

 bugs, Leptoglossus and Phtliia. are capable of carrying infection in this 

 way. Washing the bolls with weak corrosive sublimate solution, 

 which, when tried in the previous year, seemed to act as a deterrent, 

 on this occasion had negative results. 



Where an ample supply of their favourite food-plant is maintained,, 

 bush bugs may be present in considerable numbers close to cotton 

 plants Anthout injuring them, cotton being apparently low in the 

 scale of their preferred foods. The presence of Dysdercus is much 

 more to be feared than that of bush bugs, because of the fluctuating 

 effects of the latter as compared with the steady and rapid increase 

 of injury due to the former up to the end of the season. As the 

 effect of severe direct injury is to destroy or prevent the development 

 of the lint, the amount of direct injury represented in the return of 

 stained lint is small in comparison with that due to the internal and 

 bacterial boll diseases. 



Injury by these bugs to pea and bean crops was in some cases severe 

 enough to threaten complete failure of the crop. The damage is in 

 many cases increased by infection with the fungi of internal boll 

 disease, which must now" be included among the organisms causing 

 disease in leguminous crops. There is in these plants however no 

 spread of disease from seed to seed by contact as in the cotton boll. 



DE Ong (E. R.). Control of Red Spider.— 31 thJy. Bull. Cal. State 

 Commiss. Hortic, Sacramento, vii, no. 3, March 1918, 

 pp. 112-120, 3 figs. 



The term red spider is applied to three species of mites in Cali- 

 fornia, namely, Bryobia pratensis, Teiranychus mytUaspidis (citrus red 

 spider) and T. telarius {bimacidatus, sexmacidatus). T. lelarius is the 

 species of the greatest economic importance in the State, the chief 

 cultivated plants that suffer severely from its attacks being stone 

 fruits, particularly almond, prune and peach, English walnut, hops,, 

 beans, pumpkin and squash. The damage is mostly done from 

 July to September, though garden beans are sometimes infested until 

 the November frosts. Through the winter months the mites subsist 

 upon geranium, violet and other hardy winter plants. It is probable 

 that females may oviposit during warm days in winter, but the nympts 

 hatching from these eggs are usually killed by a sudden fall in tempera- 

 ture and it is not until late spring that any numbers appear, eggs then 

 hatching in 3 to 6 days, and the development to the adult form 

 requiring 12 to 18 days in hot weather. The hibernation period has not 

 been closely investigated in California, but in all probability some of 

 the mites remain on winter food-plants such as wild blackberry, 

 geranium, sowthistle {Sonchus), Chenopodium botrys, violets, holly- 

 hocks, mustard and privet, while others hibernate in the groimd at 

 the base of the trees attacked. 



Mites are largely disseminated by wind, a moderate wind carrying 

 them as far as 400 or 500 feet, and also by travelling from plant to 

 plant when the leaves are touching and by crawling over the ground. 

 Female mites are able to crawl several feet an hour over cultivated 



