Identification and Control Methods for Yellow Scale (Parlatoria proteus) Infestation on Orchids

Yellow scale, Parlatoria proteus (Curtis), belongs to the order Homoptera, family Diaspididae, and isa major pest of orchids, distributed throughout the country, with nymphs and female adults damagingorchids, jasmine, camellia, sago palm, lily-of-the-valley shrub, snake plant, citrus, orange, agave, etc. Morphological characteristics: The female adult scale cover is elongated oval, brownish-yellow, with white or grayish-white margins; the cover is thin and semi-transparent. The second exuviae spot is oval, protruding at the head end, dark in color. The female scale cover is 1.5 mm long and 5 mm wide. The male scale cover is light brown with a black exuviae spot, 0.8 mm long and 0.25 mm wide. The female adult body is broadly oval, with the mesothorax and metathorax relatively broad. The antennae bear one long bristle. There are 2-3 anterior spiracular glands. The body margin on and anterior to the anterior spiracular glands bears conical glandular spines. There are 4 groups of perivulvar pores, each group containing 4-11 glands. There are 3 pairs of well-developed pygidial lobes; the fourth segment resembles an arm spine. Occurrence pattern: It produces 2-3 generations per year, overwintering as adults and eggs. Generations are not synchronized, the oviposition period is long, the egg stage is short, and overlapping occurs in winter. In Guangzhou it can be seen almost year-round, occurring more in early summer and autumn, and is especially severe in muggy, poorly ventilated, high-humidity environments. Control methods: 1. When a small number oforchidsare damaged, scrape them off with a small knife or wipe them off with a cloth dipped in kerosene. 2. Spray 80% dichlorvos emulsion or 40% omethoate emulsion at 1000 times dilution for control. Liu Zhongjian