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VAN PoETEREX (N.). De Spruitvreter of Knopworm der Bessenstruiken, 



Incurvaria capiteUa, Fabr. | Tlic Shoot-eater or Budworiii of Hush 

 Fruit {Incurvaria eapitella, Fahr.)]~Tijdschr. over Plantenzie/den, 

 Wageningen, xxi, afd. ;5, 3r(i July 1915, pp. 61-80, 2 plates. 



Incurvaria eapitella has been long known in Westland and Bangert 

 as a pest of bush fruit, and has been reported almost every year. In 

 1909 Taschenberg described the yoimg larvae as living in the berries, 

 but this seemed somewhat doubtful, as in Bangert it is regarded as 

 certain that the eggs are to be foimd on the young wood, and rubbing 

 the wood between the fingers in order to destroy theni is commonly 

 practised. In order to test the matter, twigs with eggs on them 

 were cut, placed in pots and watered and their development watched. 

 A number of larvae of an undetermined species of Cercopis also hatched 

 in these experiments ; this insect is well known in Bangert on 

 bush fruit. 



The life-history of Incurvaria eapitella is as follows : — The moth, 

 which is described and figured, flies in the second half of May and 

 beginning of June ; the eggs are laid on the green, half-grown berries, 

 from two to four in the pulp of each. The young larvae live at first 

 within the berries, eating the yomig and still soft seeds ; the attacked 

 fruit begins to colour rapidly and ripens before its time. The larvae 

 then leave these berries for the twigs, on which they spin a web for 

 hibernation, and early in the following spring, they emerge and attack 

 the buds and young shoots, wliich they hollow out, and have thus 

 acquired their popular name ; one larva will damage several shoots 

 or buds. Early in April they are full-gro^vn and drop to the ground, 

 spin a cocoon and pupate a little below the surface. The hibernation 

 webs, which are not easy to find, generally occur about 8 inches above 

 the ground and on old wood ; the webs are more loosely constructed 

 than those of Incurvaria {Lampronia) rubiella. According to Chapman, 

 the webs occur on the bud scales at the lower end of the branches, on 

 the buds themselves and on fruiting twigs ; the author found them 

 only on the bark, more or less protected by bark scales. The wintering 

 larvae are about 3 mm. long, but lie curled up in the web in such a way 

 that the length is barely 'i mm. ; they are usually of a bright red 

 colour. The second feeding period in the spring is well known to 

 growers, and the effect on the shoots is very obvious if the attack is at 

 all severe. The buds are generally bored from the side nearest to the 

 twig, so that the frass lies between the bud and the twig ; occasionally 

 two larvae attack the same bud. An attacked twig remains some time 

 before turning black. The shoots, which are attacked later, retain 

 some of their lower leaves, but the central poition is depressed and 

 turns black, growth is arrested and the trusses of bloom never develop. 

 The control of the pest is not easy ; hand-picking the attacked shoots 

 in April has hitherto been the only remedy suggested which is of any 

 use, and this is laborious, expensive and unsatisfactory; winter 

 washes of alkali or soap and sulphur have also been tried. The 

 attacked shoots are not easily recognised, and unless a very large 

 percentage of the pests is destroyed, the method of hand-picking is 

 all but useless. The Dutch growers prune the bushes rather severely 

 and as late as possible, when the larvae have left their winter quarters 

 and passed into the buds, and in this way large numbers are quickly 



(C215) b2 



