316 



spider, which was identified as Tetranychus modestus, was found 

 nfesting maize leaves. These pests first appear in one or more small 

 colonies and at this stage are easily controlled ; when unchecked, 

 infestation spreads rapidly, becoming apparent by a shght yellowing 

 along the midrib, gradually spreading all over the blade. A mixture 

 of equal parts of air-slaked lime and flowers of sulphur dusted on 

 with a powder gun proved very effective. Any other fine powder 

 might be substituted for the lime. Maize stalks were also infested 

 with the larvae of a corn-stalk borer, which could not be definitely 

 identified as no adults were obtained, but which was apparently 

 Diatmea zcacoleUa, Dyar. Eggs are deposited on the under- surfaces 

 of leaves, the young larvae beginning to work in the bud. The mature 

 larvae leave the buds and tunnel up and down the lower part of the 

 stalk. The hibernating borers can be destroyed by cutting the stubble 

 low and ploughing it vmder and burning any refuse that is left on the 

 field. Rotation of crops is also recommended. 



Vegetable crop pests included the usual number of grasshoppers 

 and cutworms. A bug, Pycnoderes quadrimacidaius, caused consider- 

 able injury to lettuce and similar crops ; once lettuce is attacked, there 

 is no remedy available. The bugs should not be allowed to breed on 

 weeds or crops of no value and these should be sprayed with a strong 

 solution of crude oil emulsion. 



Cotton pests included Buccidairix thurberieUa (cotton leaf-miner), 

 which is effectively checked by parasites, the chief being Arthrolytus 

 aeneoviridis, Gir., Smicra sp. and HaUichella sp. The cotton stainer, 

 Dysdercus albidiventris, Stal, has unfortunately appeared in Arizona. 

 D. minms, Say, has also been recorded, but not on cotton. Precautions 

 are recommended against allowing the stainer to breed on weeds and 

 plants in the neighbourhood of cotton fields ; in the fields the insects 

 should be collected and destroyed wherever possible. 



Mackenna (J.). Report on the Progress of Agricultitre in India for 

 1915-1916, Calcutta, pp. 50-56. [Received 20th May 1917.] 



Experiments continued at Pusa showed thp-t there are at least 

 five different species of Rhogas which parasitise cotton boll-worms 

 [Earias] and that these may be a valuable means of control. The 

 Jassid bug known as " maho " [Nephotetfix], a serious pest of growing 

 rice, was controlled by collection in bag nets. Nymphida depmictalis, 

 a caterpillar that feeds on rice plants, was controlled by putting 

 kerosene in the water of the rice fields. Sugar-cane borers include 

 two or more species of Diatraea, and these may occasionally attack 

 other cereal crops such as maize, millet, etc., though the normal 

 borers of these are rarely found on sugar-cane. These pests may be 

 controlled by varying the time of planting. To protect cane setts 

 from termites lead arsenate was found to be the best insecticide. 

 Spraying operations were carried out to check the green scale [Coccus 

 viridis] on coffee and experiments were made with a parasitic fungus. 

 It was found that the liability of tea bushes to attack by the tea mos- 

 quito [Helopeltis] can be lessened by the addition of soluble plant foods 

 to the soil. Various insecticides were successfully tried on termites and 

 thrips attacking tea. The European olive fly [Dacus oleae] was 

 discovered in wild olives in N.W. India. The lime treatment of stored 



