- 期刊
- OpenAccess
Ecology of the Brown Planthopper (Nilaparvata lugens (Stål)) During the Winter Season in Taiwan
摘要
In Taiwan, the brown planthopper (BPH), Nilaparvata lugens (Stål) is formerly considered to be able to overwinter on some alternate host plants, while the results of the present work reveal the fact that BPH is rather belong to a monophagous insect. They can complete their normal development on paddy plant only. According to the results of the inoculation test of BPH carry out in the winter season, among tested 35 species of plants, only the paddy plant, including the ratoon is recognized as mere host plant in strict sense. Besides, water wild-rice (Zizania aquatica Linn.), Taiwan barnyard grass (Echinochloa crus-galli,(Linn.)), bareet grass (Leersia hexandra Swartz), corn (Zea mays, Linn.), and small flower umbrella plant (Cyperus difformis, Linn.) are recognized as temporary host plants. The adults of BPH can survive for 8 to 20 days on these plants, but no progeny is emerged from them. Although the paddy plant is a favorable host plant for BPH, it complete 1 generation during the winter season in Taipei. The rate of population increment during this season is quite limited. The field survey on the BPH population is conducted from Feb. 1979 to Jan. 1982 with islandwide. It show the general tendency that the population begin to decrease from late autumn to the end of January. The minimum density is showed at the beginning or middle of February. However, the increment of the population is observed at the beginning of March. According to the laboratory test, the critical low temperature of BPH estimate as 11°C. On the other hand, the average temperature of the winter season is around 16°C in the northern parts of Taiwan. The fact indicate that BPH is tolerable and can bear in winter season in Taipei. While, in the case of the cold climate striking in Taiwan, the temperature may be lower than 10°C for temporarily. The influence of the cold climate attack on the BPH population is also analyzed in the present work. The result of the outdoor inoculation test suggest the possibility that the overwintered population of BPH produce 2 generations on the 1st rice crop season from the end of March to the middle of June, and may occur 1 or 2 another generations to the harvest.