Effects Of Magnetic Field And LED (Light Emitting Diode) Illumination On Biological Characters Of The Diamondback Moth, Plutella Xylosetella.L

The diamondback moth (Plutella xylosetella.L) is one of the most important pests of cruciferous vegetables.It has characters of long-distance migration and phototaxis. The effects of different intensities of magnetic field and different wavelengths of LED lights on biological characters of the diamondback moth were investigated in this paper. The results are as follows:1. The effects of different intensities of magnetic field on biological characters of the diamondback moth were investigated. Different intensities of magnetic field (150 mT, 200 mT, 300 mT, 360 mT, 520 mT) had significant effects on biology of the diamondback moth. The results indicated that the development durations of egg, larva, pupa were longer than the control when treated by all 5 intensities, and the higher the intensity was, the longer the development duration was. When treated by magnetic field with intensities of 360 mT,520 mT, the longevity of the diamondback moth adults decreased 5 days than the control, and the fecundity decreased by 50%. Different intensities of magnetic field had significant effects on pupation rate and eclosion rate, while there was no obvious effect on egg hatching. pupation rate of the diamondback moth were significantly lower than the control when treated by magnetic field with all 5 intensities, when the value was only 53.96% under 520mT intensity. Emergence rates were obviously lower than the control under all densities except 150 mT.2. The activities of protective enzymes and detoxification enzymes of the diamondback moth were significantly affected by magnetic field of different intensities. When treated by magnetic field with intensities of 200 mT,300 mT,360 mT,520 mT, the activities of SOD and POD decreased significantly. When treated by magnetic field with intensities of 300 mT,360 mT,520 mT, the activities of CarE were obviously lower than the control. The magnetic field with 520mT intensity was most effective in decreasing the activities of GST. 3. The phototaxis of the diamondback moth for LED lights under five different wavelengths (624 nm (red),520 nm (green),465 nm (blue),590 nm (yellow),white light) were investigated.The results showed that the ratio of phototacctic(ordered from high to low) insects to the five lights were green >white>red>yellow>blue. The experiment of the phototaxis of the diamondback moth at different emergency days indicated that the phototaxis to green,white and red were the highest at the first emergency day, while to yellow and blue were the highest at the third emergency day. The phototaxis had no significant difference between male and female. The effect on the diamondback moth's phototactic behaviour after treated in dark showed that their phototactic rate ,which was treated 80min in dark under red,green,yellow and white light were significantly lower than 0min,20min,40min and 60min.4. The impact of 520 nm LED light on fecundity and egg hatching rate of the diamondback moth was studied. The results indicated that when treated the fecundity,egg hatching rate and duration of lay egg for the diamondback moth under 520 nm LED light were significantly lower than that of under darkness.