جستجوی مقالات مرتبط با کلیدواژه « ipm » در نشریات گروه « گیاهپزشکی »

In Egypt, serious piercing-sucking pests such as the western flower thrips, Frankliniella occidentalis, white fly, Bemisia tabaci, the broad mite, Polyphagotarsonemus latus, and the two-spotted spider mite, Tetranychus urticae cause significant yield losses in sweet pepper crop grown in greenhouses. The purpose of this research is to assess the effectiveness of two phytoseiid mites, Amblyseius swirskii and Neoseiulus californicus, as biological control agents for piercing-sucking pests on sweet pepper in greenhouses, compared with chemical acaricides. Three release rates were assessed: 10 adults of A. swirskii/plant, 10 adults of N. californicus/plant, and 7 adults of A. swirskii + 7 adults of N. californicus combined. The highest population density of B. tabaci and F. occidentalis was on yellow ‘Qiuda’ followed by significant damage with T. urticae. Red ‘Grand bell’, on the contrary, was consistently more susceptible to T. urticae and moderately prone to whitefly infestation. Both biological and chemical pest control were efficient in reducing pest populations on sweet pepper in greenhouses. The results indicated that A. swirskii, alone or in combination with N. californicus, was more effective against F. occidentalis, B. tabaci, and P. latus on both pepper cultivars than acaricides sprayed under the same conditions. Moreover, the predatory mite, N. californicus, outperformed A. swirskii and acaricides against T. urticae. Together, the predatory mites, A. swirskii and N. californicus can improve biological control of piercing-sucking pests. The yield increased by 37.4 to 40.0% over the control treatment using the biological control candidates. Furthermore, biological control program resulted in the highest cost reductions for sweet pepper production (35.7–40.7 and 16.2–27.2%) compared to the control and acaricides treatments, as well as a safe yield free of chemical residues.

The Indian meal moth, Plodia interpunctella (Hubner), is one of the main economic pests of stored products, including dried figs, in Iran and the world. In this research, the effect of different doses of gamma radiation (50-1000 Gy) and temperature (20-35 ± 1 °C) was investigated on the life stages of P. interpunctella. The results showed that P. interpunctella eggs and adults exposed to gamma radiation (50 Gy) died after a short time. Therefore these stages are so sensitive to gamma radiation and were not used for further investigation on a combination of gamma radiation and temperature. In all temperatures, the survival period of larvae significantly decreased with increased radiation doses, especially at 600, 800, and 1000 Gy. Similarly, at 33 and 35 °C, low gamma radiation doses (50, 100, and 200 Gy) caused early larval mortality. In all temperatures, doses of 800 and 1000 Gy of gamma radiation resulted in 100% mortality of pupae; thereby, adult emergence declined to zero. However, in lower radiation doses of 50, 100, and 200 Gy and at 35 °C, the pupal mortality increased to 70, 70, and 83.33%, respectively. Results are promising for the integrated management of P. interpunctella on dried figs in storage.

Insects, especially Drosophila are used for genetic, immune system, and histochemical studies. Insect genome studies have resolved epigenomic, metabolomics, physionomics, transcriptomics, evolution and many other biological problems. Differences in gene and alleles within the population of one insect species can produce variations in characters or different genotypes. Genomic studies can be used for solving some of the insect pest population variation problems. This article intends to describe general applications of insect genomic studies with an example of its application to solve insect pest management (IPM ) problems.

Tuta absoluta is one of the most important pests of tomato in many countries. Emamectin benzoate (EB) is widely used in the control of lepidopteran pests, but there is sparse information available regarding its sublethal effects on T. absoluta. In this research, the lethal and sublethal effects of EB were investigated on T. absoluta under laboratory conditions. Acute toxicity bioassay was carried out on 2nd instar larvae using residue contact method. The LC50 value was 14.50 mg a.i. L−1, for 24 h exposure time. LC10 and LC30 of the insecticide was used for sublethal effect study. The insecticide significantly extended the larval developmental time at LC30. Pupal weight, fecundity and longevity of female adults were decreased at both tested concentrations. However, the LC10 and LC30 of the insecticide had no significant effects on pupal period, egg hatchability, and male adults’ longevity at sublethal effect study. These results suggest that the sublethal effects of EB might affect pest population dynamics significantly by delaying its development, and decreasing its reproduction. Hence, this bioinsecticide can be used in integrated pest management program of T. absoluta if its efficacy proven under the field and greenhouse conditions.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is a serious pest that infests different agricultural crops in Bangladesh. The application of different types of pesticides (botanical and chemical) with various modes of action and bio-pesticides was used for the first time to develop sustainable pest control strategies against spider mites. In this study, the effects of six chemical insecticides viz. abamectin, bifenthrin, bifenazate, etoxazole, hexythiazox, and spinosad, and entomopathogenic fungus Beauveria bassiana and botanical neem oil were evaluated against adult and egg stages of T. urticae under laboratory conditions. Treated mites were kept in controlled conditions at 25 ± 1 ℃, 60–70% RH and a photoperiod of 16:8 h (L: D). The LC50 values of all chemicals [for adults, abamectin (0.51 ml/L), bifenthrin (3.26 ml/L), bifenazate (3.82 ml/L), hexythiazox (3.27 ml/L) and spinosad (3.83 ml/L); for eggs, abamectin (0.56 ml/L), bifenthrin (3.48 ml/L), bifenazate (26.81 ml/L), hexythiazox (4.18 ml/L) and spinosad (18.28 ml/L)] suggest that they were effective against eggs and adult females of the T. urticae. Etoxazole (LC50 = 3.99 ml/L) is recommended against egg stage. The neem oil was found to be moderately effective (for adult, LC50 = 1.26%; for egg, LC50 = 1.77%) against eggs and adult females of T. urticae. The B. bassiana was also found to be effective against eggs and adult females of T. urticae. Finally, it could be concluded that all chemicals used in this study are effective for the management of two spotted spider mite but the entomopathogenic fungus B. bassiana and botanical neem oil were promising alternatives for successful management of T. urticae in IPM programs.

The cabbage aphid, Brevicoryne brassicae (Hemiptera: Aphididae), is an important pest of rapeseed. In this study, the effects of a silicon-based fertilizer, silicate potassium (SP), and salicylic acid (SA) on inducing resistance in rapeseed to the aphid were studied under field conditions. The rapeseed plants were directly sprayed with SP and SA at two application rates, and the population density of alive and parasitized aphids by Diaeretiella rapae (Hymenoptera: Braconidae) was recorded every three days. The results showed that the aphid population densities in SP and SA treatments were significantly lower than in control (2.21 and 3.53 folds, respectively). The lowest population density was observed in the SP treatment (1200 g/ ha). Moreover, the parasitized aphid densities in the treatments were significantly increased, and the highest parasitism was recorded in the SP treatment (1200 g/ha). The rapeseed yield in the SP-treated plants was significantly more than control, and the highest yield increase was observed in SP treatment (1200 g/ha). According to the results, SP at 1200 g/ha is recommended for cultural control of B. brassicae in the rapeseed fields.

Macrolophus pygmaeus (Rambur) is a generalist predator that naturally colonizes and commercially is used as a biological control agent of various arthropod pests of agricultural crops. Since pesticides compatibility with natural enemies is a main concern for IPM programs, the aim of the current study was to assess the lethal and sublethal side effects of two acaricides, propargite and fenpyroximate widely used to control phytophagous mites. In bioassay experiments, M. pygmaeus adult individuals were fed on the two-spotted spider mite eggs immersed in the different concentrations of both chemicals during 24 hours. Probit analysis represented that LC50 values of propargite and fenpyroximate were 3.41 and 5.74 mg (ai) L-1, respectively. Demographic analysis performed with LC30 of each acaricides using the age-stage, two-sex life table procedure. Results showed that both chemicals had significant effects on the developmental time of all stages, the total pre-oviposition period (TPOP), the adult pre-oviposition period (APOP) and females’ fecundity. Also, all main population statistics were affected by the sublethal concentrations. The intrinsic rate of increase (r) was 0.15 day-1 in the control. However, this parameter in propargite and fenpyroximate treatments declined to 0.057 and 0.083 day-1, respectively. The net reproductive rate (R0) in control, propargite and fenpyroximate treated insects was 99.96, 21.16, and 71.5 offspring/individual, respectively. Mean generation time (T) in control showed 30.08 days, whilst it was 53.17, and 51.02 days in propargite and fenpyroximate sublethal treated insects, respectively. Consequently, the results achieved in this study showed that both acaricides have potential to affect the predator, adversely. Thus, they are not suitable for IPM programs in agricultural systems where this mirid bug exists as a capable biocontrol agent.

Essential oils are environmentally benign agents which are used as alternative compounds for chemical pesticides in order to control pests. Thus, in the current study, the toxicity and repellency effects of essential oils, extracted from three medicinal plants of the Lamiaceae family, including Thymus daenensis, Satureja khuzestanica, and S. bakhtiarica, were evaluated against a resistant (MhR) and a susceptible (KrS) population of Tetranychus urticae. Results based on probit analysis revealed that all extracted essential oils to some extent showed both repellency and toxicity effects on both populations of the mite. The LC50 values of S. khuzestanica extract were the lowest against the both populations (31.16 µL. L−1 air for KrS population and 56.29 µL. L−1 air for MhR population). Also, all extracted essential oils were found to be repellent to the adult females of both MhR and KrS populations, with higher repellency effect of S. khuzestanica oil. The effect of the LC20 of the essential oils on detoxifying enzymes including Glutathione S-transferases (GSTs), esterases (ESTs) and cytochrome P450 monooxygenases (P450) was tested against both populations. Significant higher activity of all enzymes was detected in MhR population regardless of essential oils treatment. The activity of GSTs and esterases increased significantly in mites treated with all essential oils, while a tendency for a decrease in P450 activity was detected following essential oils treatment. These results indicate that the essential oils of the all selected plants, especially S. khuzestanica, have a good potential to be used in integrated management programs of T. urticae which is a serious pest in the greenhouses.

The effects of four insecticides, abamectin (1500 and 750mgl-1), emamectin benzoate (1000 and 500mgl-1), acetamiprid (500 and 250mgl-1), and flubendiamide (500 and 250mgl-1), were studied on different preimaginal stages of T. brassicae and T. evanescens, the egg  parasitoids of tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae). Parasitized eggs of the Angoumois grain moth Sitotroga cerealella (Lepidoptera: Gelechiidae) were treated by the dipping method at the larval, prepupal, and pupal stages of the parasitoid. For persistence
evaluation, the insecticides were applied at the recommended concentration on tomato plants by a hand sprayer till runoff point. Plants were maintained under a transparent polyethylene rain cover in the field. Leaves of the treated tomato plants were sampled and transferred to the laboratory at time intervals of 3, 5, 16, and 31 days after application. Based on our study, abamectin was the most harmful insecticide for immature stages of both parasitoids T. brassicae and T. evanescence. Treatment by abamectin at the pupal stage had more adverse effects
compared to prepupal or larval stages. Acetamiprid with 30.5% and 31.6% mortality in less than five days was classified as the short-lived insecticide for T. brassicae and T. evanescens, respectively. The same result was obtained in flubendiamide treatment which caused 27.2% and 26.1% mortality to the parasitoids, respectively. Abamectin with 16.1% and 13.8% mortality in less than 16 days was slightly persistent. However, emamectin benzoate with 13.3% and 15.5% mortality in less than 30 days was classified as moderately persistent for those two species, respectively. Therefore, flubendiamide and acetamiprid were non-harmful to both T. brassicae and T. evanescence wasps and are good candidates to be incorporated into IPM programs in combination with biological agents for the control of tomato leaf miner T. absoluta. By contrast, emamectin and abamectin should be used with greater care as a part of an IPM procedure.