Relationships between the occurrence of misshapen fruit on late-season strawberry in the United Kingdom and infestation by insects, particularly the European tarnished plant bug, Lygus rugulipennis

In experiments in which the European tarnished plant bug, Lygus rugulipenni s, was caged on the developing flowers or young fruits of strawberry, the i nsects caused malformation of the fruits. Another species of capsid, Plagio gnathus chrysanthemi, caused similar damage; this species is less numerous than L. rugulipennis on late-season crops of strawberry in UK. Other insect s which sometimes occur in large numbers in the flowers of late-season stra wberry, i.e. various species of thrips and pollen beetles, did not cause fr uit malformation in caging experiments, though thrips sometimes caused disc oloration of the fruit. In field experiments where numbers of L. rugulipenn is were reduced by the use of insecticides, the amount of misshapen fruit w as reduced greatly compared to untreated plots. Correlations between the nu mbers of L. rugulipennis present at the early stages of fruit development a nd damage scores for fruit deformity were highly significant. This capsid i s likely to be the major cause of fruit malformation in late-season crops o f strawberry in the UK.