Study On The Limiting Factors Of Osmia Excavata Alfken Populations And Screening Of Safe Control Chemicals For Parasiticmites

To clarify the factors that limiting Osmia excavata Alfken,one of the most important insect pollinators of apples in Shandong Province,and therefore maintain this important ecological service.Analysis of restriction factors to Osmia excavata Alfken populations to provide theoretical references for sustainable use of Osmia resources.And the security fungicide screening for Osmia excavata Alfken against the parasitic mites to provide guidance for chemical control of parasitic mites.Osmia excavata Alfken populations from 6 locations of Shandong Province were compared with life table method.And we conducted the toxicity measurement of 11 pesticides and 4 commonly used reagents to Osmia excavata Alfken,parasitic mite and bee cocoons.Main results were as follows:1 Analysis of restriction factors to Osmia excavata Alfken populationsThere were significant differences in the cocoon rates?7.64%⁷3.84%?and cocoon numbers per tube?0.80⁵.56?among the 6 locations.All population trend index were more than 1,and varied from 1.80 to 11.80.The exclusive index of population control?EIPC?of natural death,parasitism,egg Un-hatched and predation were 2.53,1.10,1.07,1.03,respectively.Total EIPC of the 6 locations varied from1.19 to 5.50,which indicated that O.excavata populations would increase 19%⁴50%without those lethal factors.Natural death of O.excavata is the main limiting factor in Shandong orchards,and improving their breeding management can decrease the natural mortality rate.?2 Security fungicide screening for Osmia excavata Alfken against the parasitic mitesAmitraz,lactic acid,sodium hypochlorite,and acetic acid were highly efficient against mite(LC₅₀=81.805 mg/L,0.06 mg/L,0.14 mg/L,0.34 mg/L respectively)and harmless to adult wasps(LC₅₀=170.051 mg/L,0.6 mg/L,0.3 mg/L,0.47 mg/L respectively).Amitraz,lactic acid and acetic acid were safer against wasp cocoons(LC₅₀=5653.299 mg/L,0.47 mg/L,0.59 mg/L respectively).Sodium hypochlorite had no toxicity to wasp cocoons.Pyridaben had good effect to parasitic mite?LC50=648.581 mg/L?and had high security to wasp cocoons(LC₅₀=7441.916 mg/L),but it was not safe to wasps?LC50=24.888 mg/L?.It is recommended that it prohibited to use during the wasp emergence,pyridaben can be used in the cocoons stage of wasp.Avermectin had a good effect to wasps,its cocoons and parasitic mites(LC₅₀=0.767 mg/L,122.66 mg/L,126.543 mg/L).Avermectin can be used for preliminary treatment of the hive and wasp tubes.We recommend to use amitraz,lactic acid,sodium hypochlorite and glacial acetic acid which are highly efficient against mite and harmless to adult wasps.Fenpyroximate,emamectin benzoate,dicofol and formic acid have a poor effect on mites and high effect on cocoons.Therefore,these pesticides are not recommended to be used.