Orchid insect pest-- black whitefly

The whitefly Aleurocanthus sPiniferus Quaint belongs to Homoptera, whitefly family. Distributed in southern China, larvae endanger rose, orchid, rose, clove, sweet-scented osmanthus, camellia, magnolia and so on. With its larvae gathering the back of the leaves, the oral needle was pierced into the plant tissue to absorb juice, the injured area showed macula, the branches of the heavy leaves blackened, the leaves fell off, and the whole plant withered. In addition to direct harm, and the excretion of a large amount of honey, transparent dew drops on the lower leaves, inducing coal fouling disease, inhibiting growth, resulting in death and falling off, affecting the appearance.

Morphological features:

Adults: male and female are similar, body length 1.0~1.3mm, body orange, covered with waxy white powder. The forewings are purple-brown, with 7 irregular white markings, the hind wings are small, lavender, foot yellow, and the male is smaller.

Eggs: about 0.25mm long, milky yellow at first birth, dark yellow before hatching, banana-shaped, tip pointed, base with

Small handle.

Nymph: newly hatched oval, flat, yellowish, about 0.2mm long, with serrated margin around the body, four tail hairs at the tail end, glossy, white wax layer secreted around the body, 14 pairs of spiny hairs on the back and about 0.7mm in body length.

Pupae: black, glossy, long 0.7~11mm, raised on the back, 9 pairs of waxy bristles on the chest, 10 pairs of bristles on the abdomen, and 10-11 pairs of bristles on both sides.

Occurrence pattern:

Bemisia Tabaci has 4-5 generations a year, 4 generations a year in Jiangsu and Zhejiang provinces, overwintering as mature nymphs on the back of the host leaves, pupating in March the following year, and adult Eclosion in the first and middle of April. The peak period of nymph occurrence is in mid-late May, mid-late July, mid-late August, late September to early October, respectively. There is no overwintering phenomenon in the greenhouse, continue to breed harm, generations overlap. Adults are more likely to Eclosion in the morning. During Eclosion, they fly out of the pupa shell in a T-shaped shape, and then mate and lay eggs after Eclosion. The offspring of parthenogenesis are all males, the adult stage is 1-6 days, the eggs are scattered on the back of the leaves, and the eggs on the old leaves are more than those on the tender leaves. Each female laid 20-30 eggs, and the egg period was 10-15 days. Shortly after hatching, the larvae insert needles into the leaves to absorb juice and secrete honeydew to pollute the leaves. The nymph has a total of three instar, 20-36 days in the later stage, and pupation in the original place after the nymph matures, and the pupal stage is 7-34 days.

Prevention and control methods:

1. Maintain the environmental hygiene around the orchid garden, remove weeds, fallen branches and leaves, properly ventilated and transparent.

2. Biological control: protect natural enemies, stop or reduce the use of broad-spectrum chemicals when the population density is low and the number of natural enemies is large.

3. Chemical control: reference whitefly.

Liu Zhongjian