What is a pineapple mealybug?

Another name

Pineapple mealybug, pineapple mealybug, pineapple white scale.

Form (Figure 4-68)

Figure 4-68 pineapple cleaning scale

1. Female adult 2. Female adult 3. Antenna (♀) 4. Hind foot (♀) 5. Egg 6. Silkworm cocoon (♂)7. The victim.

The female adult is ovoid. Body length is 2.5-3mm. Pink or gray, covered with white wax powder, so the appearance is pink. Antenna 7-8 nodes, brown. There are two small round holes beside the eyes, and the oral needle bag reaches the third section of the abdomen. There are 17 pairs of puncture holes on the side of the body, which secrete wax filaments. Finally, 1 is the longest wax filament, which is about 1/4 of the body length. The puncture group on the hip flap has two large conical spines, a group of three-hole glands, and many bristles around them. There were different degrees of sclerosis in the puncture group. 16 and 17 pairs of spines have 2-4 small auxiliary spines, some bristles and a group of three-hole glands besides 2 spines. The third pair of perforations in the head and chest usually have three thorns and several auxiliary bristles. Other spines usually consist of two spines and several auxiliary bristles. There are few porous glands and tubular glands, which are located on the body surface and abdomen. Especially near the vagina. Three-pore glands are abundant and distributed on the back and ventral surface of the body. The reproductive foramen behind the ventral surface is obvious, with umbilical point and oval shape. The tibial joint of the hind foot is twice as long as the tarsal joint. Male adults are tiny and yellow-brown, with 1 pair of colorless and transparent front wings and 1 pair of slender waxy tail hairs at the end of abdomen. Eggs are short oval, about 0.35-0.38 mm long, yellow-brown at first birth and then yellow-brown. In the flocculent oocysts at the abdominal end of female adults, they are clustered or clustered into blocks, mixed with white flocculent wax, and lightly attached to host plants. Nymphs look like adult females with tentacles and feet. The body is small, and the triangular wax holes on the body surface are smaller than those of adults. There is little difference in the length of tibiofibular joint and tarsal joint of hind foot, and the reproductive hole is not obvious, and there are no large circular wax holes and tubular wax holes. The female nymph becomes an adult after molting for three times; Male nymphs molt twice and then pupate. The first instar nymph is about 0.48mm long and 0.25mm wide, with 6 antennae, and the tarsal joint of the hind foot is slightly longer than the tibial joint. There are 1 rows of tiny wax holes and hairs on the ventral back, and the 1 pair of hairs on the ventral end is slightly shorter than the tarsal joint of the hind foot. The second instar nymph is 1.2— 1.6 mm long and has 6 antennae. The tarsal joint of the hind foot is almost as long as the tibial joint. Small wax holes are scattered all over the ventral dorsum, and the long hair at the ventral end 1 is slightly longer than or equal to the tarsal joint of the hind foot. The third instar nymph is about 2mm long, with 7 antennae. The tarsal joint of the hind foot is slightly shorter than the tibiofibular joint, and tiny wax holes are scattered in the ventral back. The long hair at the ventral end 1 is obviously longer than the tarsal joint of the hind foot. Pupa (male) is similar in appearance to male adult, with exposed tentacles, wings and feet. Pupa is hidden in the long cocoon of filamentous wax, but the cocoon is often irregular in shape and mostly attached to the host plant.

Life history and habits

This insect occurs all year round in pineapple producing areas in southern China, and it is harmful from seedling stage to fruit harvesting. Nymphs and female adults often gather at the base of leaves, between leaves and stems, gaps and depressions between small fruits on fruits to suck juice, which makes plants grow poorly and leaves dry. Its excrement drips on plants, attracting ants and inducing soot disease. Ants not only feed on the excrement of mealybug, but also transport these insects to other plants to help scale insects spread. May-September is the main damage period, which is serious to the orchard. Not only does the plant grow poorly, but the fruit can't expand, and the damaged parts of pineapple show green spots. This insect is the disseminator of pineapple wilt.

This insect has 4 generations per year in Nanning/Kloc-0, 6-7 generations per year in northern Taiwan Province Province and 7-8 generations per year in Hainan Island. Female insects can be viviparous or oviparous. Viviparous is the main reason in high temperature season, and more oviparous occurs when the weather is dry and the water is low. Winter is cold, both oviparous and viviparous. Occasionally, males appear, the individuals born by parthenogenesis are females, and the offspring born after mating are males and females.

Female adults must suck the juice of the host plant before the ovaries can mature and reproduce, and the time required for their maturity varies with the suitability and temperature of food. Parasitic in juicy parts and high temperature seasons, it ripens rapidly, only 10- 15 days. Each female lays 63- 14 1 egg in summer, 42-85 eggs in winter and 1- 12 eggs a day. The life span of female adults is 47-55 days at 28-30℃. Eggs are laid in flocculent oocysts secreted by female insects. Under the condition of good nutrition, female adults can give birth for several days, and ovulation and viviparous alternate between 1-2 months. When the temperature is low and the food is not suitable, the spawning ratio increases and the mortality rate of larvae hatched by eggs is high, so the number of them is small in summer and winter.

Newborn larvae gather under or near the mother, and then gradually disperse and settle together. If the host part dies and rots, or the nymph density is too high, or meets other stimuli, it will migrate to other places. Nymphs: 1 8- 13 days, 3-6 days for 2nd instar, 4- 13 days for 3rd instar, and the overwintering period is 2 months.

Male adults are small in size, crawl on the host plants after emergence, stay still in the depression, and have a life span of only a few days. The male larval stage is about 65438 04 days in summer and 32-44 days in March and April. The pupal period is12-15 days.

The occurrence of pineapple mealybug is closely related to humidity. Rainfall often affects reproduction. Rainwater accumulates at the bottom of pineapple during heavy rain. If the parasitic mealybug on pineapple is immersed in water, most of it will die after 3 days, so it can't give birth in water, and its fertility will decrease after leaving water. Heavy rain and continuous precipitation have scouring effect on mealybug.

Prevention and cure method

1. Seedling disinfection

Insect seedlings should be fumigated1-6 hours with hydrocyanic acid (in closed plastic shed, room and cabinet, sodium cyanide1-kloc-0/6 g, sulfuric acid 15-24 ml and water 40ml/m3) before planting.

2. Soak the seedlings with chemicals to kill insects

Soaking seedlings with 500-800 times of 40% dimethoate EC or 40% omethoate EC or 8 times of turpentine mixture for 5- 10 minute before sowing can kill most of the mealybugs attached to the seedlings.

3. Disinfection of fixed planting sites

Before planting, sprinkle 0. 1% phoxim in each hole to drive away ants and prevent ants from protecting, transporting and spreading mealybug.

Step 4 spray pesticides to treat insects

Spraying turpentine mixture when scale insects occur, and using it 18-20 times in summer; Use 10 times solution in winter; The effect is very good.