Treehoppers suck plant juices. This feeding damage is slight, although the honeydew produced by treehoppers support the growth of sooty mold, which may blacken leaves and twigs when treehoppers become abundant. The adult buffalo treehopper, Stictocephala bisonia, is small (9-10 mm) and is easily recognized by its bright green or yellowish color and two projections on each "shoulder" ("horns"), giving it a buffalo-like appearance, triangular shape, and blunt head with prominent eyes. Adults are shy and fly away with a loud buzzing noise. Nymphs are tiny, light green, similar to adults, with prominent spines but without wings. Nymphs feed until August, then molt to the adults stage and move back into trees to lay eggs. There is one generation per year.
These pests are common in landscapes throughout the United States. Its hosts include ash, elm, fruit trees, especially apple, hawthorn, locus, poplar, and many herbaceous plants, including goldenrod, aster, and clover. Its green, leaf-like wings make it difficult to spot and it is generally noticed only when moving.
The real damage is done by egg-laying females. Buffalo treehopper overwinters in egg stage. Nymphs drop to ground where they feed on weeds and grasses near fruit trees. They are most commonly found on apple trees. Adults occur in the trees where they lay eggs in the twigs with their knife-like ovipositors. Yellow eggs are laid in C-shaped slits with 6-12 eggs per slit.2 The slits cause bark to appear roughened, and twigs may die back.3 The slits may develop into oval-shaped lesions and these often predispose trees to fungal infections. The pests themselves may accidentally introduce such fungal pathogens.5 The growth of heavily infested young plants may be retarded.
Pruning out twigs damaged with egg slits during winter pruning may help. However, cutting off all infested twigs in heavy infestations might destroy one- or two-year-old trees. Spray narrow-range oil on dormant deciduous trees to kill the overwintering eggs. Control weeds under young fruit trees.4,6
Credit: Lisa Ames, University of Georgia, Bugwood.org
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