. Eastern forest insects. Forest insects. COURTESY CONN. AGR. EXPT. STA. Figure 187.—Mines of the elm leaf miner, Fenusa ulmi, in elm leaves. leaving holes in the leaf. The larvae usually become mature in late June. Then they vacate their mines and drop to and enter the ground to spin their cocoons. There is one generation per year. This species appears to be most injurious to small trees in nur- series and ornamental plantings. The European alder leaf miner, Fenusa dohrnii (Tischbein), an introduced species, occurs in southeastern Canada and through- out the Northeastern States. Its hosts are
. Eastern forest insects. Forest insects. COURTESY CONN. AGR. EXPT. STA. Figure 187.—Mines of the elm leaf miner, Fenusa ulmi, in elm leaves. leaving holes in the leaf. The larvae usually become mature in late June. Then they vacate their mines and drop to and enter the ground to spin their cocoons. There is one generation per year. This species appears to be most injurious to small trees in nur- series and ornamental plantings. The European alder leaf miner, Fenusa dohrnii (Tischbein), an introduced species, occurs in southeastern Canada and through- out the Northeastern States. Its hosts are listed as alders, es- pecially the introduced European alders. Winter is spent in the larval stage in cocoons in the ground. Pupation occurs in the spring, and the adults appear and lay eggs during late May and early June. The larvae feed in the tissues of the leaf, forming blotch mines. Full-grown larvae drop to the ground to pupate, and a second generation of adults appears from late July to early September. They also lay eggs and give rise to a second generation of larvae. These become full-grown by late fall and then enter the ground to spend the winter. Profenusa thomsoni (Konow), possibly an introduced species from the Far East, is widely distributed in southeastern Canada and from Maine to Illinois and Wisconsin. Its hosts are gray, paper, and yellow birches. In Ontario, female adults were ob- served in late July and early August and laid eggs in the tissues of leaves. The larvae mined the tissues, forming light-colored, blotch mines. Up to 40 larvae were found in a single mine. When all of the tissues of a leaf were consumed, all of the larvae, re- gardless of age, vacated the mine and dropped to the ground. Of these, only those in the latter part of the fifth instar were able to enter the soil and survive. In light infestations, sucker growth up to about 4 feet tall in shaded locations was preferred. In contrast, trees up to 35 feet tall in all types of habitats wer
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
