Occurrence and control of main diseases and insect pests of sweet-scented osmanthus

Osmanthus fragrans, also known as osmanthus, is a precious aromatic plant native to China. In recent years, osmanthus plant diseases and insect pests have a rising trend, common diseases and insect pests are: anthracnose, leaf spot disease, rot disease, Jiding insect, psyllid, whitefly, scale insect, spiny moth, tortilla, lionid moth and ruler diameter, etc., combined with the control practice in recent years, the occurrence characteristics and control methods are briefly described as follows.

I. Occurrence characteristics and control methods of main diseases

1. Anthracnose: It is easy to occur in high temperature and high humidity environment, producing nearly round purple-brown spots on leaf stems, and black dots on them. When the damage is serious, dead leaves. From June to July, spray zinc 500-600 times solution for prevention. At the same time pay attention to tree ventilation and light transmission, reasonable watering and fertilization. Discovered diseased leaves shall be removed and destroyed in time, and 50% mefenamine 800-1000 times solution shall be sprayed for prevention and control. Remove litter and weeds thoroughly in winter.

2, leaf spot disease: easy to occur in high temperature and high humidity environment, irregular black spots appear on the leaves, black mold is born on the spots, causing the leaves to fall early. From June to July, spray 140 times equivalent Bordeaux mixture for prevention, spray 70% topzin 800-1000 times solution for control after disease onset; water and fertilize reasonably; pay attention to ventilation and light transmission; remove litter and burn intensively to reduce infection sources.

3, rot disease: mostly occurs in the root neck, the injured parts are water-soaked, the disease spots gradually expand, resulting in weak growth and even death of the plant. Sprinkle a small amount of sulfur powder around the plants in early spring; apply thiram kerosene to seriously affected areas.

II. Occurrence characteristics and control methods of main pests

1. Jiding insect: adults bite young leaves into defects, but mainly larvae eat in the cortex of branches. The damaged cortex has prominent cracks and flows out oily brown colloid. When the damage is serious, the bark bursts and the main branch or the whole plant dies.

A, artificial killing: adult emergence period, using its pseudo-death, in the morning dew before the vibration of branches, after landing to kill.

B, branch coating: from adult to larva damage stage, brush 20-30 times of dichlorvos emulsion, omethoate emulsion or monocrotophos emulsion on branches, repeat 3-4 times (7-10 days interval each time). 80% dichlorvos emulsion is mixed with 10-20 times clay and appropriate amount of water to make paste, which is painted on the damaged parts of branches, so that the adults after emergence are poisoned and die when they bite through the bark and come out of the hole.

C. Spraying control: 90% trichlorfon 1000 times solution can be used for crown spraying 2-3 times (about 7 days each time) to control adults.

D. Poisoning larvae: scraping bark at the peak of larva hatching, coating with 80% dichlorvos emulsion 20 times solution.

2. Psyllid: adults and nymph suck bud, leaf and tender shoot juice, brown withered spots occur on the affected leaves, and the whole leaves turn brown in severe cases, causing early defoliation. The nymph secretes a large amount of honey on the leaves, inducing soot disease. At the peak of nymph development, spray 25% carbaryl WP 200-300 times or 50% monocrotophos 2000-3000 times.

3. Whiteflies: Adults and larvae gather on the back of the leaves to suck juice, causing the leaves to turn yellow, wilt, and even die. The insect secretes large amounts of excrement, which pollutes leaves and can cause soot disease. To catch the young larvae, spray 40% speed kill 1500 times solution.

4. Scale insects: The scale insects that harm osmanthus flowers include red wax scale insects, chaff scale insects, blowing scale insects, etc. The nymph and adult of scale insects penetrate host plant tissues with their needles to absorb sap, resulting in the death of branches and leaves. At the same time, most scale insects can secrete honeydew, induce soot disease, serious damage. To master the chemical control in the young nymph stage, 40% speed kill 1500 times solution or 50% dichlorvos 1000 times solution or 40% imine 150 ml per mu can be selected.

5, thorn moth: mainly yellow thorn moth, green thorn moth, green thorn moth, flat thorn moth and so on. Most of them overwinter in cocoons, which attach to branches, trunks or soil. Adults phototaxis strong, larvae eat leaves, young larvae cluster damage, 7-8 months the most serious. Artificial removal of cocoon pupae and insect leaves. Chemical control should be carried out in time for young larvae, such as 10% cypermethrin 2000 times solution or 50% fenitrothion 150 ml per mu. Conditions can also be light trap.

6. Leaf roller moth: There are brown leaf roller moth, apple leaf roller moth and yellow leaf roller moth. Its larvae have the habit of leaf rolling and defoliation. Before the larvae roll leaves, spray 40% monocrotophos 80 ml/mu or 50% fenitrothion 200 ml/mu or 50% fenthion 120 ml/mu, etc. After rolling the bud, remove it in time or quickly pinch it from bottom to top.

7:17), and they shall be called, and they shall be called. Larvae can spin silk for cocoons, which adhere to a variety of broken branches and leaves, in various forms of sacs. Larvae in the pouch, moving the head and chest out, negative sac forward. The mature larvae pupate in the pouch and feed on leaves. Spraying 95% trichlorfon crystal 1000 times solution or 50% fenitrothion 1000 times solution or 50% fenthion 120 ml/mu etc. at young larva stage

8. Inchworm: commonly known as arch worm, larvae bite leaves, newly hatched larvae are active, can spin silk droop, disperse damage by wind, adults have phototaxis, eggs are laid in cracks in tree cortex or among branches.

Use light to trap adults. Before the first ten days of April, lime water should be used to brush the bark cracks of trees to reduce the egg laying and egg hatching rate. spray 95% trichlorfon crystal 1000 times solution or 40% phoxim 150 ml/mu or 50% fenitrothion 200 ml/mu at young larva stage.