This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesti...This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesticide residues on fresh olive tree leaves at recommended concentrations (RC) at different time intervals: 3, 10, 17, 24 and 31 days after pesticide applications. Parasitism viability (% emergence from parasitized eggs) and adult emergence time (developmental time from pupa to adult emergence) were evaluated. Regarding to the International Organization of Biological Control (IOBC) guidelines, results of toxicity effects of insecticides show that: Deltamethrin was moderately harmful to all Trichogramma species at RC (Decis®100 milliliters·ha−1), however, spinosad was harmless to moderately harmful at RC (Tracer®20 milliliters·ha−1). Trichogramma species revealed differences with regard to adult emergence time and exhibited significant changes in parasitism viability with increasing time after pesticide treatment. While deltamethrin residues affected parasitism viability 31 days after the product application, spinosad displayed similar viability for almost species 24 days after the application. The usefulness of Trichogramma parasitoids used as biological control agents, in olive tree ecosystem, was discussed in integrated pest management programs for Prays oleae control when parasitoid species were exposed during pupal stage to the insecticide residue.展开更多
Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of ...Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of the olive moth Prays oleae Bern(Lepidoptera,Yponomeutidae).Thirteen local strains were preselected on the basis of the geographical origin and the availability from mass production of the rearing host Ephestia kuehniella ZELL.(Lepidoptera,Pyralidae) under laboratory conditions.Selection tests were focusing on acceptance and preference for P.oleae eggs.In the acceptance test,a single parasitoid female was offered P.oleae eggs on "tricho-card" for 6 hours at 25°C,70% HR and L16:D9 and assessed for parasitism after 6 days.The preference was determined by offering the choice and observing contacts with eggs of the target pest P.oleae and eggs of the host E.kuehniella.Parasitism was therefore assessed 6 days after the experiment under similar laboratory conditions.In host acceptance test,most eggs of P.oleae were parasited by strains belonging to the species T.oleae,T.bourarachae and T.cacoeciae.These strains also showed a high number of contacts with olive moth eggs in preference tests.However,a small number of T.bourarachae observed ovipositions resulted in successful parasitism.Therefore,T.oleae and T.cacoeciae were selected as candidates for further experiments.展开更多
Bactrocera oleae is the most economically damaging insect of olive in the Mediterranean. As a reliable alternative to synthetic chemical insecticides, botanical pesticides from plant extracts are also considered natur...Bactrocera oleae is the most economically damaging insect of olive in the Mediterranean. As a reliable alternative to synthetic chemical insecticides, botanical pesticides from plant extracts are also considered natural control methods safe for the environment and human health. In practical applications up to date, studies demonstrating toxically effects of biological control agents on the insect have been carried out in organic farming systems based on some industrial microbial formulations. But much less attention has been given to botanical insecticides against B. oleae. Thus, a certified botanical insecticide issue from various plants and approved per Indian and International organic standards was tested against larvae and pupae of the olive pest Bactrocera oleae in the east of Tunisia under laboratory conditions. The experiments were conducted with 3 normal treatments and 1 control. Two techniques were used for larvae and pupae: direct contact using concentration from 0.5;0.750;1 and 1.5 mg/l and fumigation treatment using 2 mg/l conducted in rectangular boxes (25°C - 27°C, 75% - 85% RH and 14:10 LD photo period). For larval stages, LC50 and LC90 values for Ultra-Act were 0.45 and 1.22 mg/L in direct contact and 1.5 - 2 mg/l with fumigation, respectively. For pupal stage, the ID25 and ID50 values were estimated to be 0.71 mg and 1.26 mg respectively corresponding to the inhibition of emergence of 25% and 50% of B. oleae adults from pupa. Our results indicate that sprayed Ultra-Act product has the potential to control the three olive fly instar larvae. Pupal emergency was decreased significantly with fumigation treatment. In conclusion, Ultra-Act is a promising botanical insecticide against B. oleae that could be used as a successful alternative for chemicals in integrated control methods of this pest in Tunisia.展开更多
文摘This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesticide residues on fresh olive tree leaves at recommended concentrations (RC) at different time intervals: 3, 10, 17, 24 and 31 days after pesticide applications. Parasitism viability (% emergence from parasitized eggs) and adult emergence time (developmental time from pupa to adult emergence) were evaluated. Regarding to the International Organization of Biological Control (IOBC) guidelines, results of toxicity effects of insecticides show that: Deltamethrin was moderately harmful to all Trichogramma species at RC (Decis®100 milliliters·ha−1), however, spinosad was harmless to moderately harmful at RC (Tracer®20 milliliters·ha−1). Trichogramma species revealed differences with regard to adult emergence time and exhibited significant changes in parasitism viability with increasing time after pesticide treatment. While deltamethrin residues affected parasitism viability 31 days after the product application, spinosad displayed similar viability for almost species 24 days after the application. The usefulness of Trichogramma parasitoids used as biological control agents, in olive tree ecosystem, was discussed in integrated pest management programs for Prays oleae control when parasitoid species were exposed during pupal stage to the insecticide residue.
基金INCODEV (TRIPHELIO) (UE/ 2002-2005) :Sustainable Control of Lepidopterous Pests in Olive Groves - Integration of Egg Parasitoids and Pheromones
文摘Assessment of quality of biological control agents is an important step for the success of any biocontrol program.Experiments were carried out to select candidate Trichogramma species for use in biological control of the olive moth Prays oleae Bern(Lepidoptera,Yponomeutidae).Thirteen local strains were preselected on the basis of the geographical origin and the availability from mass production of the rearing host Ephestia kuehniella ZELL.(Lepidoptera,Pyralidae) under laboratory conditions.Selection tests were focusing on acceptance and preference for P.oleae eggs.In the acceptance test,a single parasitoid female was offered P.oleae eggs on "tricho-card" for 6 hours at 25°C,70% HR and L16:D9 and assessed for parasitism after 6 days.The preference was determined by offering the choice and observing contacts with eggs of the target pest P.oleae and eggs of the host E.kuehniella.Parasitism was therefore assessed 6 days after the experiment under similar laboratory conditions.In host acceptance test,most eggs of P.oleae were parasited by strains belonging to the species T.oleae,T.bourarachae and T.cacoeciae.These strains also showed a high number of contacts with olive moth eggs in preference tests.However,a small number of T.bourarachae observed ovipositions resulted in successful parasitism.Therefore,T.oleae and T.cacoeciae were selected as candidates for further experiments.
文摘Bactrocera oleae is the most economically damaging insect of olive in the Mediterranean. As a reliable alternative to synthetic chemical insecticides, botanical pesticides from plant extracts are also considered natural control methods safe for the environment and human health. In practical applications up to date, studies demonstrating toxically effects of biological control agents on the insect have been carried out in organic farming systems based on some industrial microbial formulations. But much less attention has been given to botanical insecticides against B. oleae. Thus, a certified botanical insecticide issue from various plants and approved per Indian and International organic standards was tested against larvae and pupae of the olive pest Bactrocera oleae in the east of Tunisia under laboratory conditions. The experiments were conducted with 3 normal treatments and 1 control. Two techniques were used for larvae and pupae: direct contact using concentration from 0.5;0.750;1 and 1.5 mg/l and fumigation treatment using 2 mg/l conducted in rectangular boxes (25°C - 27°C, 75% - 85% RH and 14:10 LD photo period). For larval stages, LC50 and LC90 values for Ultra-Act were 0.45 and 1.22 mg/L in direct contact and 1.5 - 2 mg/l with fumigation, respectively. For pupal stage, the ID25 and ID50 values were estimated to be 0.71 mg and 1.26 mg respectively corresponding to the inhibition of emergence of 25% and 50% of B. oleae adults from pupa. Our results indicate that sprayed Ultra-Act product has the potential to control the three olive fly instar larvae. Pupal emergency was decreased significantly with fumigation treatment. In conclusion, Ultra-Act is a promising botanical insecticide against B. oleae that could be used as a successful alternative for chemicals in integrated control methods of this pest in Tunisia.
