| Myzus persicae (Sulzer) belongs to Homoptera Aphididae, it is a major pest of tobacco. It not only can suck tobacco sap directly, but can excrete some secretion and transmit many virus diseases, this has heavy effect on tobacco quality. We chose tobacco fields in Feixian, Linyi, South of Shandong, investigated population dynamics of Myzus persicae (Sulzer) and several kinds of natural enemies roundly. We also examined the effect of tobacco variety, fertilization quantity and planting pattern on Myzus persicae (Sulzer), studied the effect of mothproof net and membrane crashed tobacco on Myzus persicae (Sulzer) and virus disease, discussed chemical control and integrated management technology of Myzus persicae (Sulzer).1. Myzus persicae (Sulzer) population dynamics in field were both two-apex curve in 2005 and 2006. The first apex of aphid number appeared at the end of May to the end of June, the second apex of aphid number appeared at the middle of July. The average aphid number of two apex in 2006 was higher than what in 2005. In 2005 and 2006, with eating and flowing of aphid number, ladybug's number also appeared two apex at the beginning of June and the end of July, respectively, which was the same as or little later than the apex of Myzus persicae (Sulzer). Aphidiidae only had one apex which appeared at the beginning of June, it was the same as Myzus persicae (Sulzer) basically. Then, the number rapidly fall after the middle of June. Green lacewing number present one-apex type, but the apex is later, about at the middle or end of July, that was the same as the second apex of Myzus persicae ( Sulzer) in field basically.2. There were different sensitivity among different tobacco variety to Myzus persicae. In 9 tested tobacco varieties, the most sensitive variety was K326, the next were ZC01, CF209, CHINA201, KD6, NC89 and K10, CHINA100, CF201 were the lowest sensitive. Howerve, the second apex of aphids on all tobacco varieties appeared at the beginning of July in 2007. The speciality of resisting virus disease of tobacco rested with the characteristic itself and had not direct relativity with the sensitivity of aphids.3. Different planting patterns of tobacco had obvious effect on occurrence of Myzus persicae (Sulzer). At the second apex of Myzus persicae (Sulzer)(the middle of July), the number of Myzus persicae on simplex vernal tobacco and summer tobacco were the most, the next were intercropping of tobacco and sweet potato, intercropping of tobacco and peanut, and the number of Myzus persicae on membrane crashed tobacco was the least. Howerve, before the end of June, the number of aphids on tobacco was simplex vernal tobacco> intercropping of tobacco and sweet potato, intercropping of tobacco and peanut > tobacco transplanting under plastic film and summer tobacco.4. We studied effect of different amount of applied fertilizer on the occurrenceof Myzus persicae (Sulzer). The results showed that the number of Myzus persicae (Sulzer) on tobacco which had not fertilization was the most. That of 3.5Kg and 7.5 Kg per 666.67 m~2 of applied fertilizer was fewer, and that of 5.5Kg per 666.67 m~2 of applied fertilizer was the least.5. Insect-proof screen could obstruct aphids effectively. There was no aphid on tobacco with insect-proof screens 40 days after transplanting. It inhibited the incidence of CMV and PVY completely. Insect-proof screen could also inhibit the incidence of TMV. In contrast, the incidence of CMV, PVY and TMV were 5.78%, 8.82 % and 4.37% without using insect-proof screen. The quantity, quality and benefit of tobacco increased obviously with insect-proof screen.6. Tobacco transplanting under plastic film could decrease the number of Myzus persicae (Sulzer) obviously and held up winged aphids moving to tobacco for the first time. The number of Myzus persicae on tobacco transplanting under plastic film was fewer than that of simplex vernal tobacco, it was 6.05% of simplex vernal tobacco. Tobacco transplanting under plastic film also decreased virus disease and the incidence of virus disease was less half than common cultivation. Tobacco transplanting under plastic film increased yield, production value and crackajack scale of tobacco obviously.7. The repellent rate to Myzus persicae (Sulzer) was higher than 50% 15 daysafter spraying tobacco with the dosages of 25% Thiamethoxam WG 2000 times dilution. It also could inhibit virus disease spreaded by aphids obviously. In laboratory test, the LC50 of Imidacloprid, Thiamethoxam and Acetamiprid were 0.9535, 3.0303 and 4.2984mg/L , respectively. The virulence was as 38.7, 12.2 and 8.6 times as Omethoate. Thereinto, Imidacloprid has the highest virulence.8. Myzus persicae (Sulzer) were controlled completely 14 days after treating with 5% Imidacloprid EC 2000 times, 3000 times, 25% Thiamethoxam WG 8000 times, 10000 times and 3% Acetamiprid EC 1500 times. They were ideal pesticides to control Myzus persicae (Sulzer). 5% Aldicarb could inhibit Myzus persicae (Sulzer) for a long time used in the root of tobacco when transplanted. Repellent rates were 93.6%, 96.0% and 98.0% at the dosages of 600g, 750g and 900g per 666.67 m~2. Its control rates of virus disease spreaded by aphids was more than 51.1%.9. These studies were suit for controlling Myzus persicae (Sulzer) in tobaccofields of Shandong province. |
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