ECO-Friendly Approaches For Controlling Of Storage Mites On Chinese Herbs

Laboratory studies were carried out at the Center of Chinese Medicine at Huazhong Agricultural University, Wuhan, China. The experiments aimed to estimate the influence of three ways to control two storage mites(Tyrophagus putrescentiae and Aleuroglyphus ovatus) fed on two dried medicinal Chinese herbs (Crataegus pinnatifida and Coix lachrymal-jobi). We have used antifeedants, predatory mites and Bacillus thuringiensis var. tenebrionis as bio-control agents against T. putrescentiae and A. ovatus.Pea flour (Pisum sativum L.) and bean flour (Phaseolus vulgaris L.) are toxic to some stored-product pests. In this investigation, we evaluated the toxic effect of pea flour and bean flour to T. putrescentiae and A. ovatus reared on C. pinnatifida and C lachrymal-jobi. The experiment was carried out under the optimal conditions of storage mites at25℃and85±5%RH in the dark. Pea flour and bean flour were used at five concentrations (0,0.01,0.1,1and10%). The mortalities of T. putrescentiae and A. ovatus were recorded at four periods (7,14,21and28days), while their population dynamics were determined after21days.The results showed that the use of pea and bean antifeedants were very efficient in controlling T. putrescentiae and A. ovatus on both chosen Chinese herbs. The controlling effect of pea flour and bean flour on T. putrescentiae was higher than that on A. ovatus. The low dose of pea flour (0.01%) caused33%reductions after28days in the mortality of T. putrescentiae on C. lachrymal-jobi. The concentration of1%pea flour was sufficient to kill all individuals (100%mortality) of T. putrescentiae after28days on C. pinnatifida and after21and28days on C. lachrymal-jobi. The results indicated also that adding of pea flour generally led to significant decreases in the rate of increase (r value) for T. putrescentiae and A. ovatus. At0.01%concentration of pea flour, there were no decreases noticed in the r value for A. ovatus only on C. pinnatifida. The concentration of1%pea flour had the same toxic effect as10%concentration on T. putrescentiae after28days. Therefore,1%concentration of pea flour is highly recommended in controlling T. putrescentiae on Chinese herbs. Low dose of bean flour (0.01%) generally had no toxic effect on T. putrescentiae and A. ovatus when they fed on C. lachrymal-jobi and C. pinnatifida. After28days, the concentration of1%bean flour caused81%and52%mortalities of T. putrescentiae and A. ovatus on C. pinnatifida and92%and69%on C. lachrymal-jobi. Addition of bean flour at10%on C. pinnatifida and C. lachrymal-jobi killed all individuals of T. putrescentiae and A. ovatus. The results showed also that the rate of increase (r) of T. putrescentiae and A. ovatus on C. pinnatifida and C. lachrymal-jobi, did not change considerably at0%and0.01%concentrations of bean flour. On the other hand, r values of T. putrescentiae and A. ovatus reread on C. pinnatifida and C. lachrymal-jobi were strictly decreased at other concentrations of bean flour (0.1%,1%and10%) after21days. It can be concluded that1%of bean flour is also a good concentration to control T. putrescentiae after28days on C. pinnatifida and C. lachrymal-jobi, but it is not sufficient in the case of A. ovatus.The developmental periods and female longevities and life table parameters of Cheyletus malaccensis and Neoseiulus barkeri fed on T. putrescentiae and A. ovatus on C. pinnatifida and C. lachrymal-jobi were recorded at four constant temperatures (15,20,25and30℃). The results showed that the development of immature stages, female longevities and life table parameters of C. malaccensis and N. barkeri vaired significantly due to the change of temperature degrees. The highest developmental periods of C. malaccensis and N. barkeri on T. putrescentiae were57.11and20.43days, while they were42.83and26.67days on A. ovatus at15℃in case of C. lachrymal-jobi.The longevities of C. malaccensis females on T. putrescentiae and A. ovatus decreased from61.6and67.17days at15℃to23.56and12.77days at30℃on C. pinnatifida and from50.37and57.86days at15℃to19.00and23.11days on C. lachrymal-jobi at30℃. In the case of N. barkeri, the females longevities of T. putrescentiae and A. ovatus diminished from52.12and45.68days to17.62and17.09days on C. pinnatifida, and from43.83and35.42days to15.39and12.17days when temperatures vaired from15℃to30℃.The life table parameters for C. malaccensis and N. barkeri showed different response for the temperature changes.The Ro and PDT were affected negatively as temperatures increased, whereas rm and X increased as results of temperatures decreased. The use of25℃was responsaible for the best rm values. The greatest rm values for C. malaccensis on A. ovatus were0.253on C. pinnatifida.For N. barkeri, the highest rm values on T. putrescentiae was0.162on C. pinnatifida.Mortalities of T. putrescentiae and A. ovatus increased significantly due to the increase of predator to prey ratios. The effeiceny of C. malaccensis in controlling T. putrescentiae and A. ovatus was higher than that of N. barkeri on the two herbs. Both C. malaccensis and N. barkeri showed higher increases in mortalities of T. putrescentiae and A. ovatus on C. pinnatifida than on C. lachrymal-jobi. The release of C. malaccensis at a ratio of1:10(predator to prey) caused the highest mortalities for T. putrescentiae and A. ovatus (75%and92%) on C. lachrymal-jobi. In addition, the highest mortalities for T. putrescentiae and A. ovatus (69%and56%) on C. lachrymal-jobi were recorded when N. barkeri released at the same pervious ratio.The influence of Bacillus thuringiensis (BT) at five concentrations (0,2.5,5,10and20mg/kg) on the biology and mortalities of T. putrescentiae and A. ovatus fed on the two Chinese herbs were measured at25℃under the dark conditions. The mortalities of T. putrescentiae and A. ovatus due to the use of BT were recorded after four periods (7,14,21and28days). The results showed that the use of BT had negative effects on the development and mortalities of T. putrescentiae and A. ovatus. The toxic effect of BT on T. putrescentiae and A. ovatus was higher when they fed on C. lachrymal-jobi than on C. pinnatifida.On the other hand, the longevity and fecundity of T. putrescentiae and A. ovatus females decreased as BT concentration increased.The use of BT at a rate of20mg/kg was responsible for the highest mortalities of T. putrescentiae (81.22%and90.91%) and A. ovatus (57.66%and71.90%) on C. pinnatifida and C. lachrymal-jobi after28days from the experiment beginning, respectively.