Control Techniques for Aphids, Red Spider Mites, Scale Insects, Damping-Off, Rust, and Powdery Mildew on Flowers

In spring the temperature turns warm then cold again, and the air humidity is high. At present the occurrence of crop pests and diseases is at a moderate to severe level, and flowers also suffer from many pests and diseases. The following are generally the more serious ones from April—May:

1. Damping-off

When the temperature reaches 20°C, newly sown flowers, saplings, and some flowers prone to root rot are highly susceptible to damping-off when the soil moisture is high. Control methods: 1. Before sowing, mix 1.5—4 kg of 70% quintozene evenly into the soil per seedling. 2. Control watering at the seedling stage; do not let the soil become too wet. 3. At the early stage of the disease, water with 1% ferrous sulfate or a 200—400 times dilution of 50% amobam solution, applying 2—4 kg of the solution per square meter.

2. Rust

Rose rust attacks when the rose buds are about to open. Control techniques: 1. When the roses sprout, promptly remove and burn the yellow diseased shoots that sprout first, eliminating the source of infection. 2. At the early stage of infection, spray a 700—1000 times dilution of 15% triadimefon.

3. Powdery mildew

Chinese rose powdery mildew and garden balsam powdery mildew mostly occur in May—June, and in summer they easily cause symptoms such as yellow leaves, withered leaves, and curled tender shoots. Control methods: 1. Ensure good ventilation and light for the flowers. 2. Apply less nitrogen fertilizer and more phosphorus and potassium fertilizer. 3. At the early stage of infection, spraying once with a 700—1000 times dilution of 15% triadimefon is enough.

4. Aphids

Rose of Sharon, ornamental peach, hibiscus, Chinese rose, and honeysuckle are all easily harmed by aphids. As the temperature rises, aphids also increase day by day. Control methods: 1. Mix 40% omethoate or 50% phosmet with water at 1200—1500 times dilution and spray. 2. For a small number of potted flowers, a 70—100 times dilution of neutral laundry detergent solution can also be sprayed.

5. Red spider mites

They begin to cause damage from early April to jasmine, hibiscus, asparagus fern, Chinese rose, dahlia, and others. Control methods: 1. Spray a 1000 times dilution of fenpropathrin. 2. For a small number of potted flowers, often rinse the upper and lower leaf surfaces with tap water, or spray or dip with a 100—150 times dilution of boiled and cooled flour paste water, then rinse once more with clean water after a day or two, which can achieve obvious results.

6. Scale insects (flower lice)

The scale insects on white magnolia, Chinese rose, boxwood, and pittosporum mostly begin to hatch from mid-April to mid-to-late May. Control methods: 1. Before they hatch, gently brush off the insects by hand. 2. During the larval hatching period, spray a 1000—1500 times dilution of 40% omethoate.