جستجوی مقالات مرتبط با کلیدواژه "کنترل تلفیقی" در نشریات گروه "گیاهپزشکی"

In this research, the efficiency of the parasitoid wasp, Habrobracon hebetor (Say) in integrated with Matrine and Bacillus thuringiensis (Berliner) subsp. Kurstaki (Btk) against Anagasta kuehniella (Zeller), was investigated. Lethal and sublethal concentrations (LC30) of Matrine and Btk were determined by bioassay method on host larvae. To evaluate the preference of the host larval instars by the parasitoid, different larval instars were provided for parasitoid and the rate of parasitism was determined. The fourth and the fifth instar larvae of the host were treated with sublethal concentrations of Matrine and Btk then were provided for parasitoid in choice and non- choice conditions. The rate of paralysis, parasitism, egg-laying, emergence percentage and sex ratio of release wasps were determined. The results showed that female parasitoid preferred the fourth and fifth instar larvae of the host for parasitism. In the choice test, Matrine-treated larvae were more preferred by female parasitoid while in non-choice test, the highest amount of parasitism and egg-laying was related to the control treatment. The emergence percentage of adult wasps and their sex ratio (Female/Total), obtained from Matrine-treated fourth and fifth instar larvae, were 61 and 54% in the choice and 61 and 54% in the non-choice tests. The results showed that Matrine and Btk have significant potential in controlling of A. kuehniella. However, due to the sublethal adverse effects of these control agents on the efficiency of the parasitoid, simultaneous use of them with the parasitoid wasp, H. hebetor is not recommended.

The black bean aphid, Aphis fabae </em>Scopoli (Hemiptera: Aphididae), is one of the most important pests of several cultivated crops throughout the world. The predatory bug Deraeocoris lutescens</em> (Schilling) (Hemiptera: Miridae) have privileged position in biological control of aphids such as the black bean aphid, A. fabae</em>. Recently, there has been a growing interest in research concerning the possible use of plant extracts as alternatives to synthetic insecticide. In the present study, the effect integration of natural enemy with commercial pesticides (pirimicarb and abamectin) and plant extracts Melia azedarach</em> and Peganum harmala</em>, to control of A. fabae</em> were investigated. The result showed, combination of plant extracts M. azedarach</em> and P. harmala</em> with natural enemy causes significant decrease in this pest population and M. azedarach</em> has less hazardous on natural enemies. Also, the effects of commercial pesticides and plant extracts on the prey consumption of natural enemies were evaluated. Totally, the results of these experiments indicated that the ethanolic extract of M. azedarach </em>and pirimicarb have a minimum impact on the mortality of natural enemies, and the ethanolic extract of M. azedarach </em>has a minimum impact on the feeding of natural enemies.

 Integration of different pest control tactics is a principle in modern pest management. Interaction between different tactics and possible antagonism between them then will become important. A common integration is integration of egg parasitoid, Trichogramma spp. and larvicidal microbial agent, Bacillus thuringiensis against some field crop moth-pests, particularly in bollworm-cotton system. Although sequence of application allows avoiding direct antagonism, but indirect effects on the next generation of the parasitoid via treating the target pest’s larvae is not impossible. Some direct effect via overlapping of different stages of the pest is also possible. Therefore, studying possible maternal effects on parasitoids of the next generation that are developing on B.t.-treated host larvae is required. In this study, response of T. brassicae, was studied on two kinds of hosts; first bollworm, Helicoverpa armigera eggs laid by those females that treated by LC20 of B. thuringiensis in third instar. The second one control (untreated) individuals. Life history parameters were compared between the two groups by two-sided t-test. No significant difference was observed between the two groups. It means that B.t. had no undesirable effect on T. brassicae. The mean value of R0, rm and T were 41.22 ± 3.85 female/female/generation, 0.3545 ± 0.009 /d and 10.49 ± 0.19 d as average of the two treatments. Thus, B. t. is safe for integration with Trichogramma application programs.

Integration of different pest control tactics into a larger program is a principle in modern IPM. Interaction between different tactics and possible antagonism between them then will become important. A popular integration is integration of egg parasitoids, Trichogramma spp. and larvicidal microbial agent, Bacillus thuringiensis Berliner against some field crop moth-pests, particularly in bollworm-cotton system. Although sequence of application allow avoiding direct antagonism, but indirect effects on the next generation of the parasitoid via treating the target pest’s larvae is not impossible. Some direct effect via overlapping of different stages of the pest is also possible. Therefore, studying possible maternal effects on parasitoids of the next generation that are developing on B.t.-treated host larvae is required. In this study, response of Trichogramma brassicae Bezdenko, was studied on two kinds of hosts; first bollworm, Helicoverpa armigera Hubner eggs laid by those females that treated by LC20 of B. thuringiensis in third instar. The second one control (untreated) individuals. Life history parameters were compared between the two groups by two-sided t-test. Fortunately no significant difference was observed between the two groups. It means that B.t. had no undesirable effect on T. brassicae. The mean value of R0, rm and T were 41.22 ± 3.85 female/female/generation, 0.3545 ± 0.009 /d and 10.49 ± 0.19 d as average of the two treatments. Thus, B. t. is safe for integration into Trichogramma application programs.

Bulb mites of genus Rhizoglyphus (Acari: Acaridae) have been identified as pest of many crops in storage, greenhouse, and field. The most important hosts are species of family Liliaceae (e.g. Allium spp.) Rhizoglyphus echinopus (Fumouze & Robin) (Astigmata: Acaridae) is one of the most important pest of gladiolus corms in Mahallat. The mites infest bulbs and corms by penetrating through the basal plate or outer skin layers. Bulb mites may establish in the inner layers, which makes control extremely difficult. Feeding wounds created by bulb mites provide entry sites for soil-borne fungal pathogens such as pythium, rhizoctonia and fusarium. Despite their economic importance and broad distribution, the control of R. echinopus remains in a state of confusion and needs a thorough evaluation. In addition, the field biology and ecology of this mite is not well studied, and methods for sampling, monitoring and assessment are limited. Management of bulb mites is complicated because of their short generation time, high reproductive potential, broad food niche, interactions with other pests and pathogens, and unique adaptations for dispersal. Historically, these pests have been controlled by synthetic acaricides and insecticides, which are now limited due to their resistance. Alternative control strategies, including cultural and biological control, have shown limited success, but need to be further developed and implemented. We evaluated the capacity of the soil-dwelling predatory mite, Hypoaspis (Geolaelaps) aculeifer (Canestrini) (Mesostigmata: Laelapidae), as well as disinfestations of corms to control attacking bulbs mite. The experiment was performed in 24 treatments and 3 replicates in randomized complete block design. Each plot was separated with plastic and its soil was sterilized by solarization. In addition, 30 gladiolus corms were cultivated in each plot. Disinfestations treatments (corms were soaked in poison solution for 25 minute) include: 1, 2 & 3- abamectin (0.4, 0.8, 1.2 ml/lit); 4, 5 & 6- ethion (1, 1.5, 2 ml/lit); 7, 8 & 9- fenazaquin (0.5, 1, 1.5 ml/lit); 10, 11 & 12- hot water (45°C for 25, 50 and 75 min); 13, 14 & 15- release of predator mite H. (Gaeolaelaps) aculeifer 10, 20 and 30 predator for every 100 Gladiolus bulb (previously infested with bulb mites); 16, 17 & 18- release of 100, 250 and 500 predator mites in square meter 15 days after planting; 19, 20 & 21- tap water as control treatments (30°C for 25, 50 and 75 min); 22- hot water (45°C for 25 min) and release 10 predator for every 100 gladiolus bulb; 23- hot water (45°C for 25 min) and release of 100 predator mites per square meter; 24- hot water (45°C for 25 min) and release 10 predator for every 100 gladiolus bulb and release of 100 predator mites per square meter 15 day after planting. Significant differences were found among treatments and with control (α= 0.5). In all cases, the population of predatory mites increased as long as bulb mite densities were not too low. Experiments in the greenhouse showed that in the absence of predatory mite, populations of the bulb mite, R. echinopus, on gladiolus corms increased, whereas population growth of bulb mite was slowed down as the predatory mite were released. The highest infestation severity was observed in treatments 19, 20 and 21 (control), while the lowest percentage of corms infestation were recorded in treatments 24, 23 and 22. The highest frequency of corms was produced in treatment 24, also the highest inflorescence length was found in treatments 13 and 24. The height length mean of gladiolus stem was observed in treatments 24, 23 and 13, respectively. The flowers in treatments 7, 14, 17 and 23 lived the greatest. The fastest germination rate was recorded in corms in treatments 24, 23, 22, 14, 15, 13 and 10, respectively. But the number of buds was statistically located in the same group and their differences were not significant. Based on the results and with respect to the gladiolus features, biological and integrated pest control methods could be recommended for reducing R. echinopus infestation.

This experiment was conducted in Safiabad Agricultural Research Center for two years starting from 7th October 2001 in order to evaluate and selection of the best cultural, chemical and integrated control methods of Protapion trifolii (L.) (Col.: Apionidae) in Berseem clover. The effects of control methods were investigated using 9 experimental treatments (including chemical and cultural controls, and the integration of these two methods) in the form of a 2-factor split plot design with 3 replications. Vertical factors were two insecticides, Ecamet and Durseban, and an "untreated" treatment, and horizontal factors were the dates of second mowing (for seed) in 1st, 16th & 31st March 2002. In order to evaluate the amount of damage and the effects of different control methods on yield components, the percentage of inflorescence infestation to larvae before and after spraying, the amount of seed yield, the number of seeds per inflorescence, the number of inflorescences per m2, 1000 seeds weight, the amount of fresh forage, dry forage and the amount of produced protein were recorded. The results of two years combined analysis showed no significant difference among spraying treatments for all the mentioned characteristics, except the percent of larvae infested inflorescences after spraying. Contrary to spraying treatments, there were significant differences among mowing treatments for the percent of larvae infested inflorescences before spraying, the amount of seed yield, the number of inflorescences per m2, the amount of fresh forage, dry forage and the amount of produced protein. Considering the main objective of this experiment (obtaining the highest seed yield) and the high economic value of the clover seeds, the results showed that the mowing date of 16th March 2002 could be suggested as the best date. Also, the chemical control of P. trifolii had no significant effect on seed yield despite its effect on the population of the pest itself, so probably the chemical control of this pest in seed farms of Berseem clover has no economic justification in addition to its harmful environmental effects.