Flower powdery mildew control methods to help you achieve a bountiful harvest without worry

Powdery mildew is a fungal disease that mostly affects the tender leaves, young buds, tender shoots and flower buds of flowers. The affected flowers mainly include Chinese rose, rose, rugosa rose, tree peony, gardenia, fuchsia, Chinese peony, chrysanthemum and dozens of other species. Based on the author's years of observation and control experience, here is a brief introduction.

The disease mainly occurs on leaves, and in severe cases can infect leaf stalks, tender shoots, flower shoots, flower buds, flower stalks, flower buds, petals and other parts. In the early stage, the diseased parts show nearly circular or irregular white powdery spots, and the affected areas appear slightly chlorotic or deformed. When conditions are suitable, the powdery spots expand rapidly and merge into patches, covered with white powdery mold. In severe cases, the diseased leaves become shrunken and uneven, curling toward the back, tender shoots bend downward, the flowering period is noticeably shortened, or flower buds cannot open normally. The disease occurs severely under conditions of insufficient light, poor ventilation and high air humidity. Excessive nitrogen fertilizer application, calcium deficiency in the soil, or overly dry light sandy soil all favor the onset of the disease. Drastic temperature changes and overly dry potting soil also favor the occurrence of the disease. The control methods are as follows:

1. The soil and containers used must be strictly sterilized.

2. When propagating, choose and plant disease-resistant varieties. For Chinese rose, for example, you can choose Baijin, Nushen, Ai, Similada, Jinfenghuang, etc.

3. Cultivation environment. Pay attention to ventilation and light transmission, and appropriately reduce air humidity.

4. Reasonable fertilization. Nitrogen, phosphorus and potassium should be used in combination, especially increasing phosphorus and potassium fertilizer, to improve the disease resistance of the plants.

5. In early spring before bud break, spray with 3-4 degrees Baume lime sulfur mixture (do not use lime sulfur mixture on cineraria, to avoid severe phytotoxicity), or add a small amount of laundry detergent to a 0.5 degree Baume lime sulfur mixture (add 50 grams per 50 kg of solution), which can eliminate the overwintering pathogens within the bud scales. Before the disease occurs, you can also spray 65% zineb 600 times dilution for protection. After the disease occurs, promptly prune and burn the diseased branches and leaves, then spray 50% carbendazim 500-800 times dilution, with an application interval of 10-15 days; or use 0.01% potassium permanganate solution for spraying at 4-5 pm, with an interval of 2-3 days, for 2-3 consecutive times, and the effect is also quite good.