Dispersal of First Instar Larvae of the Felted Beech Scale, Cryptococcus fagisuga
1980; Wiley; Volume: 17; Issue: 3 Linguagem: Inglês
10.2307/2402634
ISSN1365-2664
Autores Tópico(s)Hemiptera Insect Studies
Resumo(1) Dispersal of Cryptococcus fagisuga in a beech forest was studied using suction traps and sticky traps. (2) First instar larvae and eggs of C. fagisuga had mean terminal velocities of about 27 cm s-I and 40 cm s I respectively. (3) The larvae were the main dispersive stage and were carried passively downwind from infested trees. (4) In mean windspeeds of < 1 m s -1 larvae dispersed a mean distance of about 10 m from a source tree which was infested from near ground level to the lower canopy. (5) The distance dispersed was proportional to height of take-off and windspeed. (6) In suction traps sited from 1 m above the ground to 6 m above the canopy (18 m above the ground) most larvae were trapped at 1 and 3.2 m above the ground. About 0.7y. were trapped at or above the top of the canopy. (7) The larvae dispersed along a short-range steep gradient under the canopy and a potentially long-range shallow gradient above the canopy.
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