108 



are of secondary importance. P. ni^icollis and 0. marginalis are 

 natives of Britain, occurring commonly in almost every English county. 

 Both species seem to have accommodated themselves to apple as a 

 food-plant within recent years, early records giving willow, sallow, 

 alder and hazel as the hosts. Both species, and especially P. nigicollis, 

 will attack red currant and cause a spotting of the leaves, but it is not 

 known whether eggs are laid on this plant. Typical injury to apples 

 has been recorded from Cambridgeshire, Suffolk, Kent, Sussex, 

 Worcester, Hereford, Devon and Cornwall, though many clean orchards 

 are found in infected districts. Attacked orchards have no common 

 features of soil or situation, and no reason can be assigned for the 

 presence of clean orchards in infected localities. 



The habits of P. rugicollis have been studied. Egg-laying takes 

 place from the end of June to the beginning of August. Eggs obtained 

 in captivity were deeply embedded in the twigs at the base of the new 

 growth and in the wood of the previous year. In the open, the eggs 

 are laid singly, usually through the lenticels. 



The eggs remain during the autumn and winter, and give rise to 

 young bugs during the latter half of April, the earliest date recorded 

 being 14th April. When first hatched, the young insects shelter in 

 the opening leaf and flower buds. Later, they become active and 

 puncture the leaves, twigs and young fruit. The area round each 

 puncture shows serious injury ; the leaves become covered with red 

 or brown spots and the shoots are stunted and sometimes killed. 

 The terminal shoot of each branch suffers most severely and there is, 

 in consequence, an excessive production of lateral twigs. The skin 

 of attacked fruit shows rough, discoloured areas. In severe cases, the 

 fruit is very deformed, cracks appear at the positions of the original 

 punctures, and the surface becomes corky. Such fruit generally ialls 

 when half grown. From 20 to 30 per cent, of the crop of an orchard 

 may be rendered unfit for sale. Certain varieties of apples seem to be 

 more liable to attack than others, but observations from different 

 districts do not entirely agree. 



It is as yet impossible to recommend any combined action among 

 growers to prevent the spread of Capsids. The insects must be con- 

 trolled in individual orchards as they appear. The best time to kill 

 the bugs is soon after hatching. The best spraying fluids are nicotine 

 and soap and certain proprietary insecticides. In America, Black 

 Leaf 40 (nicotine sulphate) has been found most effective. The spray 

 should be thoroughly applied during the last 10 to 14 days in April, 

 or during the first week in May, according to the locality. After the 

 bugs have grown considerably, they are very apt to fall from the 

 trees if disturbed. It would seem probable that the use of winter-moth 

 bands at this period is necessary if good results are to be obtained. 

 When the period between hatching and the opening of the blossoms 

 . is sufficiently long, an attempt should be made to control the bugs 

 at the earlier period. 



Flea Beetles. — Botanical Jl., London, iv, no. 4, January 1916, 

 pp. 49-50. 



Phyltotreta nemorum (turnip flea-beetle) and Haltica oleracea (cabbage 

 flea- beetle) are well-known in Britain. In the former species, the 

 winter is passed in the adult stage, beneath the bark of trees, under 



