Control and Care Methods for Brown Soft Scale on Greenhouse Flowers

Scale insects commonly infest greenhouse flowers, and among them the most serious is the brown soft scale. The brown soft scale can harm many woody and herbaceous flowers such as Milan (Aglaia odorata), Buddha's hand (Citrus medica var. sarcodactylis), Monstera deliciosa, spider plant (Chlorophytum comosum), and Schefflera octophylla. They cluster on leaf surfaces and branch tips to suck sap, while excreting large amounts of sticky fluid that induces sooty mold, seriously affecting flower growth and ornamental value. This insect reproduces 4 to 5 generations per year and can occur year-round in greenhouses.

Adult: oval or elongated oval, flat or slightly convex, 3 mm to 4 mm long, 2.8 mm to 3.4 mm wide, yellow-brown to brown. Nymphs are small, pale yellow, and relatively soft.

Control methods:

1. Manual removal: when the number of insects is small, gently wipe them off or pick them away with a soft cloth or a matchstick.

2. Pesticide: spray 3% diesel emulsion. Check after 10 days; if the edges of the insect shells curl up and they fall off at a touch, it means the insects are dead.

3. Soil-applied pesticide: for a pot with an inner rim diameter of 15 cm, use 2 g to 3 g of pesticide, and add 2 g for every additional 5 cm. Bury 3% carbofuran granules in the potting soil, after which all routine care proceeds normally. This method can ensure no reinfestation for a relatively long period.