The effects of the lime aphid (Eucallipterus tiliae L.) (Aphididae) on the growth of the lime (Tilia X vulgaris Hayne). II. The primary production of saplings and mature trees, the energy drain imposed by the aphid populations and revised standard deviations of aphid population energy budgets.
Further observations in Britain [cf. RAE/A 60, 2745] showed that the net annual production of lime saplings (Tilia vulgaris) was 23.4 g dry matter/sapling or 17.7 mg/cm2 of leaf upper surface area. The net annual primary production of a mature lime tree 12 m high was calculated by estimating the total leaf upper surface area of the tree and multiplying by dry matter production/cm2 upper leaf surface area of saplings. The mature tree produced an estimated 39.74 kg dry matter/annum. This was converted to calories in order that the energy drain imposed by populations of Eucallipterus tiliae (L.) could be ascertained. Each leaf supported an average of five aphids throughout the season, and their feeding resulted in an energy drain of 19% of the annual net production of the tree. Twenty-six aphids/leaf would be required to drain completely the net primary production of the tree. Revised standard deviations for energy budgets of the aphid are also reported [cf. loc. cit.].