Forsythia suspensa pests and diseases and their control methods

Diseases and prevention methods of Forsythia suspensa

Leaf spot

The leaf spot disease of Forsythia suspensa is caused by infection by Ascomycetes. The pathogen first infects the leaf edge, and gradually spreads to the middle of the leaf as the disease progresses. In the later stage of the disease, the entire plant will die.

The disease begins in mid-to-late May, with July and August being the peak months. Hot, humid weather and poor ventilation are conducive to the spread of the disease.

Prevention and treatment methods

To prevent and control leaf spot disease, you must pay attention to regular pruning of branches, thinning out redundant branches and overly dense branches, and keep the plants ventilated and light-permeable.

When growing Forsythia, you should also strengthen water and fertilizer management, pay attention to nutritional balance, and avoid applying nitrogen fertilizer excessively.

If Forsythia is found to have leaf spot disease, you can spray 1200 times diluted 75% Benomyl wettable granules or 800 times diluted 50% Carbendazim wettable granules for prevention and control once every 10 days. Spraying 3-4 times in a row can effectively control the disease.

Pests of Forsythia and their control methods

Pest type

Common insect pests of Forsythia include the bordered wax cicada, the transparent sparse wax cicada, the mulberry white shield scale, the ivy round shield scale, the round-spotted leaf roller, the dazzling armyworm, the pine oak caterpillar, and the white-bearded velvet moth.

Prevention and treatment methods

If Forsythia is attacked by the above pests, different measures should be taken according to different pests.

Spray 2000 times diluted 10% imidacloprid wettable granules or 1000 times diluted 25% chlorpyrifos suspension to kill the transparent sparse wax cicada and the marginated broad-winged wax cicada.

During the peak period of nymph egg hatching, spray 400 times diluted 95% acaricide emulsion or 1000 times diluted 20% cypermethrin emulsion to kill the mulberry white shield scale.

During the adult stage of the round-spotted leaf roller, spray 3000 times diluted 3% hypertonic fenoxycarb emulsifiable concentrate to kill it.

During the larval stage of the fall armyworm, spray 3000 times diluted 20% Kangfuduo concentrated soluble substance to kill it.

Spray 3000 times diluted 3% hypertonic fenoxycarb emulsifiable concentrate during the larval stage of pine-oak caterpillars to kill them.

When the white-bearded hawk moth is causing serious damage, you can spray 1000 times diluted 1.2% nicotine to kill it.

The above methods are only applicable in the early stages of insect infestation. If the plants are seriously infested with insects, they must be treated and destroyed in a timely manner to prevent the spread.