The bioecology of Psylla uncatoides in the Hawaii Volcanoes National Park and the Acacia koaia sanctuary

Leeper, John R.
Beardsley, J.W.
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Island Ecosystems IRP, U.S. International Biological Program
Psylla uncatoides is a recent accidental introduction to the Hawaiian Islands. Its population densities are closely tied to the flush phenology of Acacia spp. The psyllid was studied on Acacia koa on the southeastern slope of Mauna Loa above 4000 ft. and on Acacia koaia on the southern slope of Kohala Mt. (3200 ft.). Psyllid counts were broken down into four categories: eggs, small nymphs, large nymphs, and adults. Terminal samples were taken to obtain egg and nymphal population estimates. Adult populations were estimated from three minute D-VAC samples. The percent new terminal growth was estimated at the time of each sample. A strong relationship between peak psyllid populations and flush die-back was observed. It was suspected that the psyllid is aiding in the spread of koa rusts, as 63% of 179 psyllid adults observed had rust spores on their integument. Several predatory insects, principally coccinellid beetles and Neuroptera, were found associated with psyllid infestations, but none were satisfactorily controlling the psyllid. No parasites or diseases of the psyllid were found in the State. We plan to evaluate the effectiveness of additional natural enemies which are being introduced from Australia, the apparent native home of the psyllid. Possible associations of other insects with the psyllid have been observed and will be investigated.
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Psylla uncatoides, Acacia koaia, Acacia koa
Leeper JR, Beardsley JW. 1973. The bioecology of Psylla uncatoides in the Hawaii Volcanoes National Park and the Acacia koaia sanctuary. Honolulu (HI): Island Ecosystems IRP, U.S. International Biological Program. International Biological Program Technical Report, 23.
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