Learn agricultural technology, find experts, ask about diseases, pay attention to the headline number of "Agricultural Belden", learn breeding and breeding techniques, and experts help farmers solve agricultural production and operation problems online, and promote farmers to increase production and income.
There are more than 190 species of pests, mainly the canopy and trunk.
To harm the canopy: there are mainly leaf mites, shell worms, scarab beetles, inchworms, thrips, locusts, leafminer moths, etc.;
For the damage to tree trunks: there are mainly small beetles, wood beetle moths, white ants, moths, slugs, snails, etc.;
Harmful seedling stage: caddisflies, crickets, etc.
New pests are constantly emerging and are pests in localized areas. Today we will focus on leaf mites and wax mites.
Overview of occurrences – new characteristics of occurrence
Leaf mites harm leaf symptoms, the left picture is harmful to old leaves, and the right picture is harmful to young leaves.
The six-point leaf mite has always been considered to be the main harm to mature leaves, and now it has been found to seriously harm young leaves.
Overview of occurrence – hazards cause serious losses
In severe cases, it can cause large-scale leaf defoliation and dead tree trunks.
The cessation of deciduous leaves has led to a reduction in production
Morphological recognition: small body size, pale yellow body.
Female: Oval, slightly wider in the middle and slightly rounded at the posterior end, most with 6 irregular dark spots on the back and 4 black spots on the part.
Male: Small, narrow and long. The end of the abdomen is slightly pointed. The feet are long and there are also irregular dark spots on the back.
• Generational development from egg, young mite, first mite, second mite to adult mite;
• There is a quiescent period before entering the first nymph, the second nymph and the mite-forming phase;
• It takes 14-17 degrees to complete a generation development at room temperature of 20-30 °C, 10-31 degrees in the adult mite stage, and lay 12-39 eggs.
• Both sexes reproduce, and the female mites wait for mating during their last rest. Each mating time is tens of seconds to a few minutes. Each male mite can mate multiple times.
• Adult mites and mites can spit silk, and many wire nets can be seen on the back of rubber leaves when the damage is severe. Adult mites have strong mobility, especially when the temperature is high, and crawl faster. Female mites can crawl 3-5 meters per hour, and male mites can travel 6-9 meters per hour.
In addition to harming rubber trees, it also harms more than 50 kinds of crops (plants) such as tung oil, citrus, guava and tea;
• Six-point leaf mites in the range of 25-35 °C can complete generational development;
• Higher temperatures are beneficial to their development and reproduction, with the minimum doubling time of population at 30°C being 2.12d, and the internal growth rate and weekly growth rate reaching 0.327 and 1.387 at 30°C;
• The intrinsic growth rate is the population growth evaluation index, and 30 °C is the optimal temperature for the growth and development of the six-point leaf mite.
• High temperatures and droughts are conducive to occurrence, and the rainy season is not conducive to them.
--------------------------------------------------------------------------------------------------------------------------------------------------------------
Pattern Recognition:
Oak paraphyle wax borer
Female adults are 3 to 6 mm, oval-shaped, dorsal bulge, dark brown to purple-black wax shell, hard, shiny during spawning. Suction mouthpiece, inner mouth type, located on the ventral surface of the precursor, normal size of the foot, normal segmentation, slightly longer tibia than tarsal joint, toothless under the claw, 2 tarsal crown hairs, 2 claw crown hairs, slender, enlarged ends. Valve depression 4, not obvious. plates are paired, triangular.
(1) The suction mouthpiece is inserted into the plant tissue, and the branches of the plant are densely covered with insect mouths; In severe cases, the branches dry up.
(2) Secretes a large amount of honeydew, which becomes the natural medium of mold, and the insect mouth harms the lower leaves and ground vegetation and soot disease occurs.
Rubber-shelled insects cause large-scale defoliation of gum trees
Mesozoan infestations cause soot disease in the leaves
Acorn wax borers develop through eggs, 1-instar nymphs, 2-instar nymphs, 3-instar nymphs to adults, with a generation period of 60-83 days;
(1) Eggs: the eggs are laid under the adult shell, and the hatching larvae crawl out from the edge of the shell after hatching;
(2) 1-instar nymphs: strong mobility, is the main insect state of a large number of spread, has obvious phototropism.
(3) 2-year-old nymphs: during the period of growth and assimilation, the feeding conditions deteriorate, and they can still move; they begin to secrete a small amount of honeydew;
(4) 3-year-old insects: secrete a large amount of honeydew, which gathers into opaque drops. It is common for ants to coexist with it; insects of this age can still move in deteriorating feeding conditions.
(5) Adult worms: the body increases sharply, the amount of eggs is as high as 1990 grains, and it secretes rich honeydew.
(6) Reproductive mode: parthenogenesis female reproduction.
Host: In addition to harming rubber, it also harms more than 160 species of fruit trees, crops and garden plants, including cassava, papaya, mango, soursop, citrus, coffee, guava, banyan tree, hibiscus, castor, etc., according to the records of more than 160 species in 36 families.
Oak bead waxworms are fond of rubber, bananas, cannabis, cassava, pumpkins and other hosts. The starting temperature of the developmental stage of the insect is 10.0 °C, and the effective accumulated temperature is 1483.5 days · degrees; the insect occurs in 3-4 generations per year in Hainan. 23~27 °C is the optimal temperature for the growth of the oak bead wax borer population, and late spring and summer are the peak periods for the occurrence of the insect.
Oak and bead wax borer mainly rely on the crawling and diffusion of hatching larvae, and can also spread naturally with the help of wind, and long-distance diffusion is mainly diffuse through seedling mobilization and other ways.