Anthrax:
It is a major common leaf disease, which harms leaves and causes leaf spot and reddish brown spot.
Prevention and control methods:
1, seeds with bacteria can be soaked in warm water at 50℃ for 20 minutes or in warm water at 55℃ for 10 minutes, and then taken out and dried before sowing. You can also soak the seeds 1 hour with 500 times of 50% carbendazim wettable powder to eliminate the germs on the surface of the seeds.
2. After the onset of gardenia, spray 500 times of 25% carbofuran wettable powder, or 1000 times of 50% benomyl wettable powder and 1000 times of 50% wettable powder.
Leaf spot:
Symptoms:
It mainly occurs on the leaves of gardenia. Most pathogens invade from the tip or edge of leaves, and the lower stems and leaves get sick first. At the early stage of infection, the leaves appeared round or nearly round lesions, light brown, brown edges and sparse wheel lines, with a diameter of 5 mm-15 mm; If it happens, the edge of the leaf is irregular, the center is brown or grayish white, the edge is brown, and the wheel lines are concentric. After several diseased spots heal, irregular large spots will be formed, which will make the leaf wither; In the later stage, many small black spots were produced and buried under the epidermis.
Prevention and control methods:
1. Cut off seriously ill leaves from trees in autumn and winter, clean up fallen leaves and destroy them centrally to reduce the source of infection.
2. Planting should not be too dense, and it should be trimmed properly to facilitate ventilation and light transmission; Try not to wet the leaves when watering, preferably in a sunny morning.
3. Spraying 1000 times of 70% thiophanate methyl wettable powder, 250-300 times of 25% carbendazim wettable powder, or 700-800 times of 75% chlorothalonil wettable powder for control. Spray every 10 day 1 time. When the disease is serious, 65% zineb 600-800 times solution or 50% carbendazim 1000 times solution can be sprayed to control the spread and expansion of the disease.
Yellowing disease:
Leaves often turn yellow easily. Yellowing is caused by many reasons, so different measures should be taken to prevent it. Yellowing disease caused by lack of fertilizer: this yellowing disease starts from the old leaves at the lower part of the plant and gradually spreads to the new leaves. Nitrogen deficiency: the leaves are yellow and the new leaves are small and crisp. Potassium deficiency: Old leaves turn from green to brown. Phosphorus deficiency: Old leaves are purple or dark red. Under the above circumstances, decomposed human excrement or cake fertilizer can be forcibly applied. Yellowing caused by iron deficiency: this yellowing disease is manifested in new leaves. At first, the leaves were pale yellow or white, and the veins were still green. In severe cases, the veins turn yellow or white, and eventually the leaves will dry up and die. Spraying 0.2%-0.5% ferrous sulfate aqueous solution can prevent this situation. Yellowing caused by magnesium deficiency: this yellowing disease is gradually developed from old leaves to new leaves, and the veins are still green. In severe cases, the leaves fall off and die. Spraying 0.7%-0.8% boron and magnesium fertilizer can prevent this situation. Overwatering, freezing, etc. , it will also cause the leaves to turn yellow, so pay special attention in the maintenance process. Add 0. 1% ferrous sulfate solution into water or spray the leaves regularly.
Polyrhachis:
There are mainly yellow thorn moths and green thorn moths. There are several obvious horizontal lines on the back and side of the larva, and there are branches on the body. The cocoon of the yellow thorn moth has a white pattern, the young larvae mainly feed in groups, the old larvae mainly feed in scattered ways, and gardenia is mainly harmed by the yellow thorn moth. After the first larvae were damaged, the leaves were transparent and reticulate, and when they grew up, the loose leaves were missing. Mature larvae cocoon under branches, trunk and shallow soil for winter. The larval damage period mainly occurs from June to September, the larval stage of 1 generation is from late June to late July, and the larval stage of the second generation is from late August to late September.
Prevention and control methods:
Larvae should be prevented in time (June-September). When larvae are concentrated, cocoons should be picked in time, branches of insect leaves should be cut off and burned. When the occurrence amount is large, pyrethroids can be sprayed. Spraying 3,000 times of 2.5% diflubenzuron EC to kill stickleback moth (the occurrence of stickleback moth varies from place to place, so it should be controlled according to local conditions).
Whitefly:
Whitefly is the main pest of gardenia. You can see that there are a lot of white-winged flying insects on the new shoots of gardenia. They gather in large numbers on new shoots, and larvae and nymphs are fixed on the back of leaves to suck juice. When it is serious, it will cause dead branches and secrete honey dew, which will lead to bituminous coal disease, whitefly likes wet environment and scattered eggs. Adults tend to be tender, always laying eggs on the tender leaves at the top with the growth of plants, which can produce 3-4 generations a year and can overlap generations for parthenogenesis. Because of its fast reproduction, strong migration ability and easy diffusion, all localities should focus on preventing and controlling overwintering adults from spawning period to first instar larvae.
Prevention and control methods:
First, agricultural measures. Strengthen cultivation management, combine pruning, cut off branches of diseases and pests and dense branches, make the courtyard ventilated and transparent, do a good job of drainage, reduce the amount of nitrogen fertilizer and increase the amount of phosphorus and potassium fertilizer.
Second, physical and biological control. Try to protect the living environment of natural enemies and trap and kill adults with yellow boards. The method of self-made yellow board is: using cardboard or plastic board, cut it into a rectangle of about 1m× 0.3m, paint it orange, coat it with a layer of sticky oil (mixed with engine oil and a little butter), put it in the garden, which is equivalent to the height of gardenia, and then vibrate the branches to trap and kill adults.
Third, chemical control. The selected pesticides are 90% trichlorfon 800- 1000 times, or 40% omethoate EC 1500 times, or 25% chlorpyrifos 1500 times, or imidacloprid 100 times, or 65438. 20% acaricide is 65,438+0,000-65,438+0,500 times, and it can also cure red spider, spraying 65,438+0 times every 7 days or so, and spraying for 2-3 times continuously.
Fourth, matters needing attention. Pay attention to the back of leaves when spraying, and spray with weeds on the ground and surrounding hosts; Because parasitic bees are very sensitive to pyrethroid pesticides, pyrethroid pesticides should be used less at this stage to protect natural enemies; Carefully use Qingying emulsion in bud stage, and do a good job in drug screening, mixing and alternate use; Organize unified prevention and control in time, and adopt the method of preventing diseases and insects first.
Scale insect:
The scale insects that harm gardenia are mainly Ceratoides rubra, which is a kind of scale insects. In winter, indoor ventilation is poor, and the temperature and humidity are too high, which is prone to the harm of scale insects and accompanied by soot disease. Scale insects can be scraped off with bamboo sticks and sprayed with 40% omethoate EC 1500 times. 20 # petroleum emulsion can also be added with 200 times of water for spray control. Or spray 40% chlorpromazine EC 1500 times or Huabao 100 times for prevention and control.
Aphids:
Spray with 10% omethoate emulsion 1000 times or malathion emulsion 1000 to 1500 times or dichlorvos EC 1000 times.
Black mold
Clean water can be used to scrub or spray carbendazim 1000 times solution.