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An Unwelcome Guest in China: A Pine-Feeding Mealybug

1996; Oxford University Press; Volume: 94; Issue: 10 Linguagem: Inglês

10.1093/jof/94.10.27

1938-3746

Jianghua Sun, Gary L. DeBarr, Tong‐Xian Liu, C. Wayne Berisford, Stephen R. Clarke,

Insect-Plant Interactions and Control

This story began inJanuary 1988.Two business representatives from the Seed Company of the Ministry of Forestry, People's Republic of China, visited the Southern Seed Company in Baldwin, Georgia, during a seed-buying trip.Just before leaving, they collected 70 scions from slash pines (Pinus elliottii) in a second-generation seed orchard.No quarantine restrictions exist for plant material leaving the United States, and the scions unfortunately were not subjected to the normal quarantine procedures required by the Chinese Animal and Plant Quarantine Law.Instead, they were shipped directly to Hongling Seed Orchard in Taishan City, Guangdong Province (fig. 1, p. 28), in southern China.This 11 l-hectare orchard of donal material was established in 1964 with 38 superior slash pines from the United States (Kellison et al. 1982).The imported scions, inadvertently carrying the pine-feeding mealybug (Oracella acuta), were immediately grafted onto slash pine root stock and almost all survived.(During the winter months, the tiny mealybug crawlers-first-instar nymphs-are located between the pine needles beneath the needle fascicles; this probably explains how they entered China undetected.)Vegetative propagation was continued in 1989.Through repeated graftings, 2,460 new scions were obtained from the original cuttings.The newly grafted trees covered a planting area of 12.4 hectares.The first sign of trouble appeared in May 1990, when a heavy growth of sooty mold was observed.Accumulations of sooty mold are usually associated with large populations of sucking insects such as aphids, whiteflies, scale insects, or mealybugs.These insects produce copious amounts of honeydew, a nutrient-rich excretion that promotes prodigious fungal growth.Inspections in early June 1990 revealed large numbers of an unknown mealybug on the scions of the newly grafted trees and on older trees nearby.The provincial government asked Chinas forest entomologists and scale insect systematists to identify the pest, determine its origin, and recommend eradication or control procedures.Local authorities initially speculated it might be Pseudococcus pini (= Crisicoccuspini ), a mealybug species native to Japan.Specimens were sent to Yang pinglan, an authority on scale insects at the Shanghai Insti-Chinese laborers spray in-tute of Entomology.In secticides on slash pines in the summer of 1990, . the Hongling Seed Orchard Yang requested assisto eradicate Oracella acura.