91 



connection between the percentage of infestation and the damage done, 

 nor between the attacks of the weevil and the size of the clover heads. 

 Mowing increases the number of flowers in the head by 50-60 per cent. ; 

 both the percentage of infestation and the damage done are lower in 

 the case of mown clover. Wild clover provides favourable conditions 

 for the breeding of Apiou before invading cultivated areas. 



This report also includes an account of the investigation into different 

 vegetable insecticides [see this Review, Ser. A, v, p. 24] and gives a list 

 of insect pests recorded during the year. Hyponomeuta 'malineUus, 

 Zell., was not numerous, while H. padi, Zell., was present in large 

 numbers and seriously injured bird-cherry trees in some localities, 

 but did not attack apples. Owing to the attacks of parasites, the 

 numbers of Aporia cratoegi were smaller than in the previous year. 

 Other orchard pests were Malacosoma neustria, Euproctis chrysorrhoea, 

 Episema {Diloha) coeruhcephala, Cheimatobia hrumata, Psylla mali, 

 which did a great deal of damage and was controlled by fumigating 

 with tobacco chist and straw, and a number of Aphids, including Aphis 

 ribis on cherries, Aphis cerasi and others. Coccinella septenipundata 

 was active in destroying these pests, though some cocoons of Perilitus, 

 terminatus, Nees, a Braconid parasite of Coccinellids were found 

 amongst them. Great damage was done by Anthononius pomorum, L., 

 the oviposition period being nnich extended, so that at the end of May 

 damaged -buds contained both larvae and pupae. Red currants were 

 attacked by two generations of Pteroniis ribesii (Nematus ventricosus), 

 and it was found experimentally that the injured berries lose up to 

 48 per cent, of their weight, besides being inferior in flavour. The 

 second generation was effectively checked by spraying with " Mortus." 

 Injuries by Eriophyes pyri to pear leaves were observed nearly every- 

 where. PhyUotretu spp. attacked cabbages, radishes and kidney beans 

 throughout the summer ; powdering with ashes and basic slag proved 

 very effective, while spraying with Paris green (4i oz. of green, 4^ oz. 

 of lime, or 2| lb. of soap in about 3 gallons of water) was unsatisfactory. 

 Mustard was attacked by P. atra, and barley and wheat in the same 

 locality by P. vittata. Sheets covered with adhesives may be used 

 against both these pests. Pieris brassicae, P. rapi, P. napi, and 

 Barathra{Mn)nestra)brassicaewei'evevy injurious, the last-named being 

 parasitised by an unidentified Chalcid. Chortophila brassicae was 

 reported from several localities, as was also Gryllotalpa gryllotalpa. 

 Agriotes lineatus and Athous niger attacked beets, potatoes and winter 

 crops. 



Several tables are given showing the distribution in time of Euxoa 

 segeium and Feltia exclamationis, as indicated by the numbers caught 

 in troughs with molasses, the maximum period for both species being 

 during the first week in July. Practically no second generation 

 occurred. Of the adults of E. segeium, 80 "2 per cent, were males and 

 19 "8 per cent, females, while of F. exclamationis the males numbered 

 only 12-9 per cent, and the females 87-1 per cent. Mayetioln destructor 

 seriously injured winter rye in one locality, and the author recalls the 

 fact that in the late seventies and early eighties of the last century 

 this Cecidomyid was such a serious pest in Riazan that a special 

 bye-law was passed by the Zemstvo fixing a date-limit for the sowing 

 of winter crops. In another locality summer rye on a small area was 

 injured by Oscinclla sj). 



