Which pesticide is effective for controlling the citrus spiny whitefly?

The citrus spiny whitefly (Aleurocanthus spiniferus) is a common pest. Affected leaves develop chlorotic yellow-white spots, and as the damage worsens the spots expand into patches. So which pesticide is better for the citrus spiny whitefly?

1. Morphology of the citrus spiny whitefly

1. The adult citrus spiny whitefly is 1.0-1.3 mm long, orange-yellow, covered with a waxy white powdery substance. The forewings are purplish-brown with 7 irregular white spots.

2. The nymph of the citrus spiny whitefly is 0.7 mm long, black, with 14 pairs of bristles on its back and a distinct white waxy ring secreted around the body margin.

3. The egg of the citrus spiny whitefly is long kidney-shaped, adhered to the underside of leaves, pale yellow when first laid and purplish-black before hatching.

4. The pupa of the citrus spiny whitefly is oval, 0.7-1 mm long, glossy jet-black, with a serrated shell edge, a relatively wide white waxy margin around the rim, a noticeably raised back, 9 pairs of long spines on the thorax and 10 pairs of long spines on the abdomen. On the lateral margins, females have 11 pairs of long spines and males have 10 pairs.

2. How to control the citrus spiny whitefly?

1. Strengthen management, prune sensibly and ensure good ventilation and light penetration, which can reduce its occurrence and damage.

2. Before sprouting in early spring, in combination with the control of pests such as scale insects, aphids and red spiders, spray diesel emulsion or clay diesel emulsion with an oil content of 5%, which has a good effect in killing overwintering nymphs.

3. During the peak occurrence of the nymphs of the citrus spiny whitefly, spray 40% omethoate, 50% naled, 25% phosmet or 50% fenitrothion each at 1000 times dilution, or 5% fipronil suspension concentrate at 1500 times dilution, or 20% imidacloprid (Confidor) soluble concentrate at 3000-4000 times dilution. Great effort should be made to control the first generation.

The citrus spiny whitefly often damages crops such as Chinese rose, orchids, cinnamon, clove and grapes, so control work should be done promptly to avoid relatively serious damage.