Types of Garden Enemies
Control. For either beetle use rotenone or pyrethrum dust during the cutting season, DDT dust in summer.

BARK BEETLES
are small, stubby beetles which make galleries in trees between bark and wood. On removing the bark, which is usually covered with small round exit holes of the beetle, you can see engraving on the wood, sculptured main galleries along which the females have laid their eggs, and smaller galleries bored by the larvae at right angles to the egg chambers. Bark beetles are enormously damaging in forests, killing billions of board feet of timber, and they sometimes take their toll of spruce and pine in ornamental plantings. Most important to eastern communities, however, are the bark beetles that spread spores of the Dutch elm disease fungus.

SMALLER EUROPEAN ELM BARK BEETLE {Scolytus multistriatus).
Reddish brown, not over 1/8 inch long, with a toothlike projection from the undersurface of the abdomen. The grubs are white, legless, % inch long, somewhat curved, much larger at the head end. Breeding is in dead elms or logs or in sickly portions of living trees. The female lays eggs in a brood gallery that runs for about 2 inches longitudinally in the wood, and the larvae tunnel out horizontally, pupating in the outer bark. The beetles, coming out of their "shot-hole" exits, fly to healthy elms to feed on the twigs before moving on to dying wood to breed. When trees are infected with Dutch elm disease, spores formed in the galleries cling to the beetles as they emerge and healthy trees are inoculated during the feeding process.

The NATIVE ELM BARK BEETLE (Hylurgopinus rufipes) also spreads the elm disease but apparently more often in Canada than in the United States. It is a reddish-black beetle, not so shiny as its European cousin, and it makes brood galleries transversely in the wood.

Control. Weak wood should be promptly removed; infested wood should be burned or treated before beetles emerge in May. To prevent the disease two sprays are now recommended: the first and most important is a dormant spray of 2% DDT for a hydraulic sprayer or 121/2% DDT for a mist blower, followed by a foliar spray in June or July first half that strength. This heavy dosage of DDT will increase mites; so a miticide should be included in the spray.

BLISTER BEETLES (Epicauta spp.).
Slender, sleek beetles, up to an inch long, all black, or black striped with yellow or margined with gray, with prominent heads and rather soft wing covers that do not entirely cover tip of the abdomen. As larvae, changing from the curious triungulins with strong jaws and long legs to more typical grubs, they feed on grasshopper eggs and so can be considered beneficial




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