What is an orange aphid?

Another name

Tea aphids, insects, drilling insects, tea aphids, etc.

Form (Figure 4- 19)

Figure 4- 19 dictyophora indusiata

1. Aphids with wings 2. Aphids without wings. Tail 4. Egg 5. The victim.

The wingless parthenogenetic aphid is oval, 2.0 mm long and 65438 0 mm wide. The body is dark brown or black, shiny and sometimes reddish brown. There are wrinkles on the head, reticulation on the chest and back, slight reticulation on the ventral back and obvious reticulation on the ventral surface. The valve is round, occasionally open and gray-black. Internodes are gray. The tumor is located in the first and seventh segments of the chest and abdomen, and the tumor at the edge of the seventh segment is the largest. The middle thoracoabdominal branch has a short handle, or the arms are separated. Short body hair, 10 head; Abdominal nodes 1-7 have 1-2 pairs of hairs, middle hairs 1 pairs, and 8 nodes have 1 pairs of hairs. The middle frontal tumor is slightly longer, and the frontal tumor bulges outward. The antenna length is 1.5mm, and the antenna hair is short. The beak exceeds the basal segment of the midfoot and has 1 pair of secondary bristles. The foot is smooth, and the femoral joint has oval adenoids. The abdominal tube is long and cylindrical, with a thick base and gradually tapering to the end, with a length of 0.29mm and a length of 2.8 times as wide, showing a corrugated shape. The tail piece is thick, tapered, contracted in the middle, with small spines at the end, light color at the base, no spines, and long hair of 19-25; The tail plate is rectangular with 19-25 long and short hairs; The reproductive plate has 14- 16 hairs. The winged parthenogenetic aphid is oval, with a length of 65438±0.8mm and a width of 0.83 mm. Dark brown, shiny. The antenna length is 1.5mm, the base of each node is light yellow, the 3rd-5th nodes are gradually shortened, and the 3rd node has 5-6 circular secondary sensory circles arranged in a row. The midrib of the anterior wing is bifurcated. There are 4 pairs of black spots on the back of abdomen. The ventral tube is shorter than the fourth segment of the antenna and longer than the caudal segment, and there is an obvious reticular structure at the base. The tail is thin in the middle and round at the end, about 12 hair. The egg is about 0.6 mm long and 0.24 mm wide. Oval, slightly thinner at one end, with prominent protrusions on the back, dark and shiny. Nymphs are 0.2-0.5 mm long. Wingless aphids are light brown or light yellow. If the winged aphid is brown, the third to fifth antennae are slightly equal in length, the sensory circle is not obvious, and the wing buds are ivory.

Life history and habits

There are more than 20 generations in a year. It is the dominant species in tropical areas such as Guangdong, Guangxi and Yunnan. It often occurs in winter and spring, causing damage to the back of young leaves, curling leaves and harming flowers. Annual parthenogenesis. Overwintering with wingless female aphids or old nymphs on orange trees, even without obvious overwintering phenomenon. During March-April of the following year, new shoots and young leaves were damaged, and the reproduction was the most prosperous and the harm was the strongest. In the orange area with low temperature, the eggs overwinter on the back of leaves, and the overwintering eggs begin to hatch above the daily average temperature of 4℃, reaching the peak in March-April, and the insect population is less in midsummer. In late September, the insect population rises to 10, and bisexual aphids appear at the end of autumn, and they mate to lay eggs and overwinter. 165438+ 10-65438+February spawns the most. When the population density is high, or influenced by weather and nutrition, winged aphids will be produced and migrated to the new buds of other plants to reproduce. Winged aphids are produced whenever new buds mature. Migration mostly takes place at dusk on a sunny day.

The citrus dichotomous aphid has strong reproductive ability. Under suitable conditions, a wingless parthenogenetic aphid can produce 35-45 young aphids. The optimum temperature for reproduction is about 25℃. When the average temperature is 16-25℃ and the humidity is above 70%, new shoots grow rapidly, aphids multiply rapidly, and the population reaches its peak. When the average temperature dropped to 2.5℃ that day, the mortality rate of insect population reached 45%. The average daily temperature is above 65438 00℃, and the insect population is gradually increasing. When the temperature reaches 28-30℃, the insect population decreases obviously. It grows in spring and autumn, and the number of insects reaches its peak. Every time a new bud matures, the number of insects will decrease. If the management is not good, the growth is abnormal and the results are few, except in winter and early spring, new buds will appear all year round and the number of aphids will increase.

The main natural enemies are harmonia axyridis (pllas), Thumberg, Coccinella septempunctata, Chrysopa C.sinica Tiedea, etc., and the natural enemies prey on and be preyed by Aphis glycines, Aphis flavipectus, Aphis coronatus, Tetraploid Aphis (Parragus quadifasciatus Meigen) and Aphis, etc. And Aphelinus sp.

Prevention and cure method

1. Strengthen the forecast.

When spring shoots shoot, the shoot rate of aphids reaches about 10%, and when there are 20 insects on the back of new leaves, chemical agents should be used to control them, but when there are many enemies on that day, the ratio of interest to loss is about 1∶25, chemical agents should not be used.

2. Biological control

If conditions permit, natural enemies such as ladybugs, lacewings, syrphids, etc. can be moved manually. The 50- 100 times solution of No.26 aphid killer has a good control effect on orange aphids, with higher temperature and better effect.

3. Chemical control

In the early stage of aphid occurrence, the trees that reached the control index were selected as follows: 50% phoxim EC 3000 times solution; 50% malathion EC 3000 times; 300-500 times of 2.5% derris extract; Spray cotton oil soap 120 times on the back of leaves.