تأثير بعض عناصر المكافحة المتكاملة في بعض جوانب الأداء الحياتي لحشرة ثاقبة الحبوب الصغرى Rhyzopertha dominica (Fab.) (Coleoptera : Bostrichidae)

Effect of some Integrated Pest Management elements on some biological aspects of lesser grain borer Rhyzopertha dominica (Fab.) (Coleoptera : Bostrichidae)

Lesser grains borer Rhyzopertha dominica ( Fab.) Was Considered as an important economic in insect on grains crop especially Wheat, rice, maize, cassava, millet etc. in storage. Its causes an important economic lose in production and quality  Therefore the present study aimed to study a control of lesser grains borer in laboratory condition by physical and biological control.                                                                      The biological control effects of fungal suspension Metarhizium  anisopliae and  chitin synthesis inhibitor (Buprofezin) Applaud was evaluated on different developments stages of lesser grain borer R. dominica (Fab.) by the treatment of eggs, larvae, pupa  and adults with different concentrations of above mentioned Insect Growth Regulators in laboratory and the physical control include ultra violate radiation(UV) exposing  at Length wave 312nm. The results showed the following:            There was significant effect of the different concentrations of the spore suspension of the fungus M. anisopliae on the Mortality percentage of stage different of the R. dominica. The results showed that the treatment of eggs with different concentrations of fungal suspension M. anisopliae the eggs at age (1-2) days were more susceptible than the eggs at age (5-6) days the mortality of eggs reached at the highest concentration was the most 1×10⁷ spor.ml^-1 was 53.60% effective in inhibitions of egg hatching when the newly laid eggs were treated, while mortality of eggs were 30.54% for eggs at age (5-6) days a period of incubation an eggs and mortality of larva which development from eggs treatment affective negatively . However the growth of the larvae emerged from those eggs was treated. The mortality of 2^nd and 4^th larvae stages were the most susceptible to suspension of the fungus Which caused 80.00, 60.00 % respectively after 12 days from treatment and the 2^nd larva stage more susceptible from  4^th larvae stages  a percentage emergence which development from larva treatment were an affective negatively an 2^nd and 4^th larvae stages treatment with suspension of the fungus in all concentrations therefore  reached 0.00%  at  1×10⁶ and 1×10⁷ spor.ml^-1 at  2^th larvae stages treatment. Treatment of pupa by suspension of the fungus increased  coincide  with increased of concentration in both sex and age (1-3),(5-6)days. Males pupa more affective from female pupa in both ages. The adults which treatment with spore  suspension of the fungus shows increased mortality and decreased longevity coincide  increased of spore  suspension of the fungus.

  The physical control Used ultraviolet radiation(UV)   an egg at age (1-2) days exposed   at length wave 312 nm  with different period times (10,15,20 minutes)  was more susceptible from an egg (5-6) days the mortality were 55.86, 5.53% respectively at exposed  25 minutes. Mortality of  larva which development from the eggs treatment  at age (1-2) days  affective negatively reached 18.91% . Morphological deformations were noticed in pupa stage as a result of an egg treatment with UV in all period times  and this treatment was also the adult emergence from some intact pupae  decreased at an egg(1-2) days in all period times  compared an egg(5-6) days.

The   mortality of  2^nd and 4^th   larvae stages were the most susceptible to ultra violate exposed (15,20,25 minutes) Which caused 54.78 , 37.42 % for 2^nd and 4^th   larvae stages respectively at exposed 25 minutes and pupal deformation percentage which development from larva treatment were 31.33,26.30% respectively.  while such percentage of emergency of adults was achieved 4^th larvae stage 34.32% and 13.30% at 2^nd larvae treatment. A percentage emergence which development from larva treatment were an affective negatively an 2^nd and 4^th larvae stages treatment with UV radiation in all period times but the emergence  at 2^nd larvae stages lesser than  4^th larvae stages.

The mortality rates of  pupal stages(1-3,5-6)days (male and female pupae) of         R. dominica (Fab.) were increased as the exposed times(25,30,35 minutes)  the highest time 35 minutes of mortality were 41.15, 37.34% males and females at (1-3) days while 32.18, 28.77% males and females at(5-6)days respectively.

The results also showed that adults emergency from pupal stage were exposed with 35 minutes were significantly affected . These all pupae males and females at ages  (1-3) days reached adult emergency 46.60,46.30% males and females while 63.70, 55.66 %  at ages (5-6) days  respectively.Males irradiated as pupae at age (5-6) days exposing at different times periods (30,35,40 minutes) mated with adult female unirradiated showed a decrease in the average number of eggs lying , percentage hatching and emergence of adults in the same time increase mortality of larvae and pupae which development from parent treatment coincide increase of times irradiated. Also obtained the same results when mated males unirradiated with adult female irradiated .

Applaud treatment the results shows : An eggs at age (1-2) days treatment with more susceptible from (5-6) days with different concentrations of Buprofezin.                      Exposing eggs by different concentrations of Applaud results showed that when the eggs at age (1-2) days treated by spraying 1500 ppm the percentage dead of eggs reached 46.03 % While was relatively more affected an concentration 2000 ppm reached to 42.80 % when the eggs treated at age(5-6) days at all used concentrations.    As far as the accumulative mortality was concerned , the results of 2^nd and 4^th stages of larvae when treated by spraying and fed on treated food with different concentrations showed that 2^nd larvae were the most affected comparative 4^th stage and the relation between the accumulative mortalities were correlated positively with the used concentrations , but negatively with the age of treated larvae . The accumulative mortality reached to 90.00 % after 9 days of treatment of 2^nd stages at the highest concentration used 2000 ppm , while reached to 53.66 % when the 4^th stage were treated at same concentration . Morphological deformations were noticed in pupa stage as a result of larvae treatment with Applaud and this treatment was also the adult emergence from some intact pupae depending on the used concentrations .     Adults feeding on treated food with IGR(Buprofezin) it is period of hatching were significantly affected . It was also found that the reproductive potential of those adults was decreased at 1500,2000  ppm concentrations the number of eggs laid by such adult reached to 25.66, 21.33 % respectively .

Meanwhile  dead of eggs laid increased depending on used concentrations reached 58.41 % at 2000 ppm . The results showed increase that the sterility index (SI%) coincide with  high concentrations .At 2000 ppm of Applaud the SI% reached to 89.60 %  while it was 57.37 % in 500 ppm .