The Effects Of Different Host Plants And Plant Growth Regulators On The Growth And Development Of Myzus Persicae (Sulzer)

The aphid Myzus persicae (Sulzer), as the host of the parasitoid Aphidius gifuensis Ashmead, is still artificially mass reared by tobacco Nicotiana tabacum L., but it spends more time and energy to plant tobacco, which directly affects the efficiency and cost of rearing parasitoids. Five plants, rape Brassica campestris L., radish Raphanus sativus L., cabbage Brassica pekinensis L., tobacco Nicotiana tabacum L. and aubergine Solanum melongena L. were chosen as aphid hosts in this experiment, the survival rates and reproduction differences for three consecutive generations on different hosts were compared; the influence of four plant growth regulators on agronomic traits, plant height, stem girth, leaf number and leaf area on tobacco were studied; the effects of plant growth regulator to the aphid survival rate and reproduction were also studied. Effects of different host plants on the aphid survival rate and reproduction showed:the survival rate and average daily fecundity per female of 1st generation on cabbage and aubergine were the highest; both the survival rate and average daily fecundity per female of 2nd generation on radish were the highest, then cabbage; the survival rate and average daily fecundity per female of 3rd generation on cabbage were the highest, then radish; the reproduction decreased obviously rearing aphids on aubergine for three consecutive generations, so aubergine was not a suitable aphid host as artificial mass rearing. Rearing aphids for three consecutive generations on rape, the survival rate was the lowest among all the host plants, and the reproduction was also lower than that on tobacco. Therefore, radish and cabbage could be taken as the suitable hosts instead of tobacco. The experiment on host choice of winged aphid showed:the winged aphid had equally high tropism to cabbage compared with tobacco, the reproduction also had no obvious difference to tobacco, the result indicated that winged aphid was also fond of cabbage. The experiment that effects of different plant growth regulators on agronomic traits of tobacco showed:it had the best control effect on tobacco growth in the treatment of 100mg/kg,200mg/kg,400mg/kg paclobutrazol and 5mg/kg, 10mg/kg,20mg/kg uniconazole. These treatments could promote vigorous seedlings meanwhile. The effects of chlormequat and prohexadiadione calcium were not obvious. The experiment that effects of plant growth regulator on the survival rate and reproduction of aphid showed:after spraying paclobutrazol and uniconazole on tobacco, comparing to the control, the survival rate of the aphid decreased in different degree at initial stage, the preoviposition stage was longer, the average fecundity of per female was also lower than the control.In the later period, the survival rate and reproduction generally improved, but they were still lower than the control. Paclobutrazol and uniconazole had a certain influence to the growth and development of aphid, the influence of paclobutrazol was greater than uniconazole, and the influence of higher concentration treatment was greater than the lower concentration treatment. The treatment 5mg/kg uniconazole had the minimum effect to the aphids than other treatments.