254 



amhigiietta, Hb., and Melolontha melolontha, L. The pupation of 

 the larvae of Melolontha begins in the first half of July and is complete 

 by the end of August ; from the middle of September to the beginning 

 of November newly emerged beetles may be found in the soil, the 

 insects hibernating in the adult stage. In 1914 the adults were very 

 numerous. The larvae are not cannibals in the sense that they devour 

 each other, but they often attack and wound one another and these 

 wounds, however slight, often prove fatal, as they provide means of 

 entry for noxious bacteria. The chief bacteria causing the death of 

 the larvae are : Bacillvs graphitosus and B. septiciis insectorum, to 

 which must be added Micrococcus nigrofaciens, recently discovered in 

 America. These also attack Scarabaeid larvae, and in the case of 

 Rhizoirogvs infection occurs even in the absence of wounds. As 

 regards measures against Melolontha, experiments have been made 

 with the one used in the South of France, consisting of immersmg the 

 roots of vine-seedlings before planting in a poisonous fluid composed 

 of about 9 oz. sodium arsenate, 18 oz. lead acetate, 2 lb. gelatine, 2 lb. 

 powder of Aloe capensis, 21b. finely ground lime and 20 gals, water ; 

 but the results were rather indefinite. 



Among pests of fruit trees, Eriosoma lanigervm, Hausm., appeared 

 in some districts, having been imported from Rumania and from the 

 government of Cherson. A statement made in the previous report 

 as to the hibernation of Evlecanium cerasi, L., is now corrected, as 

 further observations have shown that the larvae which were found 

 hibernating on fallen leaves are those of Aleurodids. The control of scale- 

 insects may be effected by smearing the trunks and branches of infested 

 trees in winter, or in any case before the buds swell, with pure kerosene, 

 or by spraying or smearing wdth 3 per cent, sulphide of lime or Cahf ornia 

 mixture. Observations on Hoplocampa fulvicornis, Klug, have shown 

 that this sawfly has only one generation during the summer, the larvae 

 leaving the trees and pupating in the soil at the end of May or the 

 begiiming of June, remaining in that stage till the middle of the follomng 

 April. The cocoons are scattered in the ground round the tree over 

 an area having a diameter corresponding to that of the crown. At- 

 tempts have been made to find some means of delaying the exit of the 

 imago from the soil, so as to allow the trees to form fruits before they 

 appear. Ramming the soil twice during April was tried and the results 

 obtained, although not conclusive, tend to show that, when done in 

 time, this may destroy a considerable number of the cocoons, as well 

 as delaying the emergence of the remainder. 



Pests of field-crops included the larvae of Lema melanojm, which 

 are able to resist many powerful insecticides ; but the fact that they 

 are covered with a considerable amount of slime was utihsed to test 

 the effect of powdering with mixtures of cement, sand and Paris 

 green [see this Review, Ser. A, iv, p. 218]. Pyrausta nuhilalis {Botys 

 silacealis) has greatly increased of late in Bessarabia ; besides the 

 usual remedies, the sowing of an American variety of maize (Long- 

 fellow) as a trap- crop has been suggested ; it is thought probable that 

 sowing of millet may serve the same purpose. 



Experiments were carried out to test the effect of various insecticides 

 on plants ; 1| per cent. California mixture (1| lb. of sulphur, H lb. of 

 slaked lime, 1| lb. of salt in 3 gallons of water) slightly scorched leaves 

 of apricots, while leaves of pears, apples and plums were unaffected 



