Orchid insect pest-- whitefly

White whitefly Trialeurodes vaporariorum Westwood, belonging to Homoptera, whitefly family. In the 1970s, with the introduction of foreign seedlings and fruits into our country, it spread to all parts of the country. Harm orchid, inverted Admiralty, Dahlia, Fusang, chrysanthemum, rose, peony and other 16 families more than 200 species of plants. Adults and nymphs use mouthparts to pierce the mesophyll on the back of the leaves to absorb juice, which makes the leaves curl, chlorosis, yellowing, and even wither. In addition, Bemisia Tabaci excreted a large amount of honeydew, contaminated stems and leaves caused coal fouling disease, a layer of black mold occurred on the leaves, affecting flowering and ornamental value.

Morphological features:

Adult: body length 1.O~1.2mm, light yellow or light green, covered with white powder wax, red compound eyes, short filamentous antennae, membranous wings, and one wing vein on each wing.

Eggs: long oval, 0.2~O.25mm, with short egg stalk, yellowish at first birth, then black.

Nymph: flat, oval, yellowish green, about O.5mm in length.

Pupa: oval, raised light yellow.

Pupa shell: flat, long oval, yellowish, translucent, the back of the whole pupa shell is covered with white flocculent wax filaments.

Occurrence pattern:

Greenhouse is the main overwintering place of whitefly, and it can continue to breed in winter. After the next spring, it gradually migrated and spread from the overwintering site to the sunny border and open field flowers. The adult density increased rapidly from July to August, and the damage was serious from August to September. After the last ten days of October, the temperature dropped, the number of insect population decreased gradually, and began to transfer to the greenhouse and continue to breed. It occurs continuously in the greenhouse all the year round, and 1O~12 generation can occur every year. The overlap of generations is obvious, and all kinds of insect states can be seen in the same period. Both adults and nymphs prefer to live in the upper tender leaves, inhabit and lay eggs on the back of the leaves, and the females mostly lay eggs on the upper tender leaves, and the distribution of each insect state on the plant forms a certain rule. the uppermost tender leaves are the adults and the first yellowish eggs, and the lower leaves are mostly the first-instar nymphs, then the middle-aged nymphs and the lowest leaf pupae. Adults are generally inactive, but when the temperature is high and the sun is abundant, it can be seen to fly between plants. Adults have a strong tendency to yellow, but avoid white and silver gray. The adult camp has sexual reproduction and parthenogenesis, but the offspring of parthenogenesis are all males. After hatching, the nymph is fixed on the back of the leaf to suck the harm. The insect spreads with the wind and the introduction and transportation of host plants.

Prevention and control methods:

1. White trapping and avoidance. The adults of whitefly have a strong tendency to yellow. Hanging white or silver-white plastic strips on the doors, windows and vents of the greenhouse can avoid the invasion of adults, and can hang or insert yellow boards next to flower plants and apply sticky oil to play an obvious trapping and killing effect.

2. Chemical control: chemical control should be controlled at the stage of spot tablets, with 40% dimethoate EC.

50% malathion EC, 80% dichlorvos EC, 20% diclofenac EC, 1000 times liquid spray, it is better to use the drug at the stage of 1 ~ 2 instar nymph, the spraying should pay attention to the concentrated plant and the high density of insect population on the back of the upper leaf.

3. Pay attention to the hygiene of orchid nursery or greenhouse, clean up weeds and leaves in time, and also pay attention to quarantine. Orchid insect pest-- whitefly

Liu Zhongjian

White whitefly Trialeurodes vaporariorum Westwood, belonging to Homoptera, whitefly family. In the 1970s, with the introduction of foreign seedlings and fruits into our country, it spread to all parts of the country. Harm orchid, inverted Admiralty, Dahlia, Fusang, chrysanthemum, rose, peony and other 16 families more than 200 species of plants. Adults and nymphs use mouthparts to pierce the mesophyll on the back of the leaves to absorb juice, which makes the leaves curl, chlorosis, yellowing, and even wither. In addition, Bemisia Tabaci excreted a large amount of honeydew, contaminated stems and leaves caused coal fouling disease, a layer of black mold occurred on the leaves, affecting flowering and ornamental value.

Morphological features:

Adult: body length 1.O~1.2mm, light yellow or light green, covered with white powder wax, red compound eyes, short filamentous antennae, membranous wings, and one wing vein on each wing.

Eggs: long oval, 0.2~O.25mm, with short egg stalk, yellowish at first birth, then black.

Nymph: flat, oval, yellowish green, about O.5mm in length.

Pupa: oval, raised light yellow.

Pupa shell: flat, long oval, yellowish, translucent, the back of the whole pupa shell is covered with white flocculent wax filaments.

Occurrence pattern:

Greenhouse is the main overwintering place of whitefly, and it can continue to breed in winter. After the next spring, it gradually migrated and spread from the overwintering site to the sunny border and open field flowers. The adult density increased rapidly from July to August, and the damage was serious from August to September. After the last ten days of October, the temperature dropped, the number of insect population decreased gradually, and began to transfer to the greenhouse and continue to breed. It occurs continuously in the greenhouse all the year round, and 1O~12 generation can occur every year. The overlap of generations is obvious, and all kinds of insect states can be seen in the same period. Both adults and nymphs prefer to live in the upper tender leaves, inhabit and lay eggs on the back of the leaves, and the females mostly lay eggs on the upper tender leaves, and the distribution of each insect state on the plant forms a certain rule. the uppermost tender leaves are the adults and the first yellowish eggs, and the lower leaves are mostly the first-instar nymphs, then the middle-aged nymphs and the lowest leaf pupae. Adults are generally inactive, but when the temperature is high and the sun is abundant, it can be seen to fly between plants. Adults have a strong tendency to yellow, but avoid white and silver gray. The adult camp has sexual reproduction and parthenogenesis, but the offspring of parthenogenesis are all males. After hatching, the nymph is fixed on the back of the leaf to suck the harm. The insect spreads with the wind and the introduction and transportation of host plants.

Prevention and control methods:

1. White trapping and avoidance. The adults of whitefly have a strong tendency to yellow. Hanging white or silver-white plastic strips on the doors, windows and vents of the greenhouse can avoid the invasion of adults, and can hang or insert yellow boards next to flower plants and apply sticky oil to play an obvious trapping and killing effect.

2. Chemical control: chemical control should be controlled at the stage of spot tablets, with 40% dimethoate EC.

50% malathion EC, 80% dichlorvos EC, 20% diclofenac EC, 1000 times liquid spray, it is better to use the drug at the stage of 1 ~ 2 instar nymph, the spraying should pay attention to the concentrated plant and the high density of insect population on the back of the upper leaf.

3. Pay attention to the hygiene of orchid nursery or greenhouse, clean up weeds and leaves in time, and also pay attention to quarantine.

Liu Zhongjian