جستجوی مقالات مرتبط با کلیدواژه « Mediterranean flour moth » 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 widespread Mediterranean flour moth, Ephestia kuehniella (Zeller), causes economic damage by feeding on stored products, particularly cereal flour. Pyriproxyfen is one of the most significant insect growth regulators widely used in controlling stored-product insect pests due to its low toxicity to mammals and lack of dangerous residues in food. By imitating the action of juvenile hormone, pyriproxyfen causes insect pests to experience prolonged larval development, failure to emerge as pupae or malformed pupae, absence of embryo development, and in some cases, a reduction in fecundity.
This study examined the toxicity of pyriproxyfen on E. kuehniella fifth instar larvae at 25 ± 1°C, 65 ± 5% relative humidity, and a photoperiod of 16:8 (L:D) h. The 50% lethal concentration (LC50) of the insecticide was calculated as 7.39 and 5.68 ppm at 72 and 96 h post-treatment, respectively. After preparing the desired concentrations based on the preliminary test using acetone solvent, the effect of sublethal concentrations (LC20 = 2.87, LC30 = 4.10, and LC40 = 5.56 ppm) of pyriproxyfen on mortality and survival period of fifth instar larvae was investigated.
The results of this study demonstrated that the survival period of larvae treated with LC20 (35.05 days) was significantly longer than the control group (18.85 days). One week after exposure to sublethal concentrations of pyriproxyfen, the larvae's survival rate was significantly lower than the control group. However, the survival percentage of larvae at two- and three-weeks post-treatment was not significantly different from the control.
One of the possible explanations for the shorter survival period of larvae treated with LC30 and LC40 is the greater toxicity of these concentrations against the pest and, consequently, the increase in the percentage of larval mortality in the second- and third-weeks following treatment. This study found that sublethal concentrations of pyriproxyfen could be used to control the Mediterranean flour moth under storage conditions.

The larvae of the Mediterranean flour moth, Ephestia kuehniella (Zeller), are widely used, as an alternative host, to rear some biocontrol agents such as Habrobracon hebetor (Say) for biological control programs. To enhance the quality of mass production, it is necessary to optimize the rearing of natural enemies on alternative hosts. The aim of this study was to investigate the possibility of diapause induction in the Iranian population of E. kuehniella larvae for optimizing the mass production of biocontrol agents such as H. hebetor.

To study the diapause induction in E. kuehniella larvae, the insect eggs (0.04 g) were released on 200 g of wheat flour and kept under optimal rearing conditions (25 ± 1°C, 65 ± 5% relative humidity, and 16:8 (L:D) h). After the emergence of each larval instar, they were divided into two groups. The first group included larvae that had already been reared in each instar (first to fifth instars) at 15 ± 1°C and total darkness for one week and the second group under the same conditions for two weeks. Then, the larvae of both groups were transferred to the optimal rearing conditions. After the emergence of fifth (final) instar, the percentage of larvae entered the diapause where the duration of diapause was evaluated. The control group consisted of larvae that were reared in the optimal rearing conditions.

The results revealed that 8 to 45% of the fifth instar larvae from the first group and 100% of the fifth instar larvae from the second group entered the diapause. The percentage of diapausing larvae from the first group was the highest when they were reared in the fourth or fifth instars at 15°C and total darkness. The duration of diapause in the larvae from the second group (19.41 to 20.56 days) was significantly longer than those from the first group (15.20 to 16.92 days).

The present study is the first attempt showing diapause induction in Iranian population of E. kuehniella. By increasing the availability of host larvae by inducing diapause, the efficiency of mass production of biocontrol agents such as H. hebetor can be enhanced.

It is proved that nutrients have an important role in growth, reproduction, immune and activity digestive enzyme. If insects feed on suitable and valuable food, they will have a strong immune capacity and could be better against foreign agents. In addition, larval feeding lead to produce of insects that they have high fecundity potention. This is important purpose of rearing of intermediate hosts for parasitoides. So, in the present study, some physiological properties of Ephestia kuehniella by feeding with vitamin C and sorbitol and mannitol were determined as a dietary supplement in vitro. Condition of rearing was 25±1 ºC, RH=45% and L: D=14:10 h. Treatments were including first treat: flour (99 g) + ascorbic acid (1 g), second treat: flour (97g) +sorbitol (3 g), third treat: flour (97 g) +mannitol (3 g) and forth treat: flour (100 g) as control. Experiments were done with completely randomized design. Relative growth rate (RGR) showed a significant increase in all treatments compared to control. Third instar larvae reared on nutritional diet containing vitamin C and mannitol had the highest efficiency of conversation of ingested food (ECI) (7.66±0.66%) and highest feeding deterrent index (FDI) (37.2±2.72%). The highest index of efficiency of conversation of digested food to biomass (ECD) (16.38±0.9%) was found in larvae fed on diet containing vitamin C. Chymotrypsin activity significantly increased in larvae fed on vitamin C–enriched food. Whereas, the activity of another protease, trypsin, increased by both sugars and vitamin C treatments compared to those of control. Nutritional diets containing sorbitol and mannitol sugars increased the activity of carbohydrase enzymes, alpha (0.74±0.07) and beta glucosidase (0.44±0.008) µmol/min/mg protein compared to other treatments, and decreased lipase activity in larvae fed on diet containing sorbitol (1.3±0.06) and vitamin C (0.6±0.01) µmol/min/mg protein. Mannitol did not have a positive or negative effect on lipase activity. Regarding immunology, injection of Beauveria bassiana (isolate 47) to third instar larvae resulted in a significant increase in total blood cell and immunocyte counts 4 h after treatment. In fact, the role of vitamin C was clearer in altering blood cell counts (625±48.7) in mm3 hemolymph compared with other treatments. The number of blood cells showed a decreasing trend over time up to 24 hours. In general, among the treatments, vitamin C and mannitol sugar can be considered as good choices in the Mediterranean flour moth diet. It seems that improving the quality of the larval food is effective in their digestion, digestive enzymes, and insect physiological defense potential and the objective of rearing of Ephestia kuehniella as an alternative host to natural enemies will be achieved more strongly.

Feeding of adults of stored-product moths in the genus Ephestia from water and sugar solutions as well as quantity and quality of larval diets would affect many biological properties of adults. In this study, effects of feeding of larvae from dietary glycerol, and male and female adult access to water were evaluated in the Mediterranean flour moth, Ephestia kuehniella Zeller. Larvae were reared on two different diets: wheat germ brewer’s yeast glycerol (10:1:2), and wheat germ brewer’s yeast (10:1). Some adults were allowed to drink water for two days before mating and some others had no access to water. Larval feeding from dietary glycerol, if male and female adults had no access to water, had a significant effect on female longevity, but access to water either by one or two sexes made the effect non-significant. Drinking water by the two sexes, depending on feeding of larvae from glycerol-containing or glycerol-free diets, decreased female longevity significantly and non-significantly, respectively. Presence of glycerol in larval diet had a significant effect on longevity of male adults but in contrast with females, access of male adults to water did not compensate the negative effect of glycerol-free diet. Females obtained from larval glycerol diets showed higher fecundity. Drinking water or not by one sex altered the effect of water access on fecundity by other sex. Feeding from dietary glycerol increased the percentage eggs hatched, and mating of males and females with or without access to water showed different effects on egg hatchability. In general, presence of glycerol in larval diet and drinking water by adults increased the adult's longevity and fecundity, and percentage eggs hatched was affected by larval dietary glycerol and male adult access to water.

Water is a powerful attractant for adults of many stored-product moths and applying water traps is a complementary control method for controlling these pests. In this study, the reproductive effects of six biorational compounds including Palizin®, TondExir®, Sirinol®, Worm tea, Neemarin® and Chlorocholine chloride at 2000, 5000, 8000, and 10000 ppm concentrations (dilated with 10% honey solution) were evaluated against adults of the Mediterranean flour moth ad libitum. All experiments were carried out at 25±2 ºC, 70±10% R.H., and 14:10 L:D. photoperiod.Adults fed well from prepared concentrations. Compared with the control (99.13%), Palizin, TondExir, Sirinol, Chlorocholine chloride and Worm tea had no effect on fertility but Neemarin decreased it significantly (F4,70=19.59; P=0.0001). Also neemarin had a better effect on fecundity. Male and female longevity decreased at higher rates of Palizin, Sirinol and Tond Exir compared with Neemarin, Chlorocholine chloride and Worm tea. The results showed that increasing the dose increased the toxic effects of the compounds. Higher sterility was caused by Neemarin (52.65-74.85%) followed by Palizin and Sirinol. Worm tea showed the least effects on the above-mentioned parameters and sterility percent. The highest percentage of infertile eggs (7.06-14.45%) was also observed in Neemarin treatments. Hence, if the adults of this moth are attracted to water traps or have access to these traps containing effective doses of biorational compounds (especially azadirachtin), controlling the adults of this moth would be possible. Because the toxic compounds are applied indirectly and at very small amounts in this method, lethal concentrations of synthetic insecticides could be applied as well. For such purposes, using azadirachtin or azadirachtin containing products or insecticides is recommended.

Mediterranean flour moth (MFM), Ephestia kuehniella Zeller, is considered as one of the most commonly used host for parasitoids mass rearing including Habrobracon hebetor (Say) (Hym.: Braconidae) and Trichogramma brassicae Bezdenko (Hym.: Trichogrammatidae). In this research, eight different diets with novel ingredients were applied in laboratory conditions (25±1 ° C, 60±5% RH and 14L: 10D) for mass rearing of the MFM. The results showed that the kind of diets had effect on development and reproduction of the MFM. The highest mean number of emerged adults, weight of 10 adults, weight of 100 eggs along with the shortest developmental time (from egg to adult emergence) of MFM, without any significant difference, were related to four diets including A: wheat flour, wheat bran, barley flour, yeast and glycerin, B: wheat flour, wheat bran, barley flour, yeast bread and glycerin (ratios: 41.5: 2: 43.5 : 3: 10%, respectively), C: wheat flour, wheat bran, yeast bread and glycerin (ratios: 82: 3: 10: 5%, respectively), D: wheat flour, corn flour and barley flour (with equal ratios: 33: 33: 33%). In contrast, the mean number and weight of emerged adults were significantly lower in the rest of diets. The longest developmental time (from egg to adult emergence) and highest immature mean mortality were occurred for diet G containing corn flour and diet F containing wheat flour, respectively. Therefore, the diets A, B, C, and D were proposed as the most appropriate media for mass rearing of the MFM, E. kuehniella.

In this study, two-sex life tableparameters of Ephestia kuehniella (Zeller) were studied on seven cultivars of barley (Dasht, Khorram, Sahra, Reihan03, Fajr30, 5shoor and EH-83-7) and two cultivars of wheat (Bam and Sepahan) at 25 ± 1 °C, 65 ± 5% R.H., and 16:8 (L: D) h. The shortest and the longest larval periods were recorded on Reihan03 (42.58 ± 0.69 days) and EH-83-7 (53.42 ± 0.95 days) cultivars respectively. The longest and the shortest developmental periods for E. kuehniella were found on EH-83-7 (72.12 ± 1.61 days) and on Sepahan (58.19 ± 1.00 days) cultivars respectively. The heaviest and lightest pupaewere observed on Sepahan (21.07 ± 0.77 mg) and Fajr30 (15.20 ± 0.58 mg) cultivars respectively. The intrinsic rate of increase and net reproductive rate were the highest (0.07 ± 0.00 day-1 and 87.41 ± 1.89 offspring, respectively) on Sepahan, and the lowest (0.037 ± 0.00 day-1 and 12.29 ± 0.48 offspring, respectively) on Dasht cultivars. The results indicate that Sepahan wheat cultivar is the most suitable cultivar for the laboratory rearing of E. kuehniella.

Factors hindering the development of inundative biological control are insect rearing costs and provide an adequate amount of natural enemies at the appropriate time. Storage of natural enemies is a useful technique to increase time flexibility of parasitoids production، and coincide the natural enemies release with pest outbreaks period، and also could reduce costs of mass production. Another way for parasitoids، is to keep host of natural enemies instead of biocontrol agent in cold. In this way because of lack of necessity to survive insect hosts after storage، temperature range and storage periods can be much more than that for predators and parasitoids. In this work، the effects of storage time of host eggs Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) on the qualitative characteristics of Trichogramma brassicae Bezdenko (Hym.: Trichogrammatidae) were studied. Regarding to identification of Wolbachia-infected strain of T. brassicae and relative advantages of thelytokous strain، these treatments were applied on thelytokous and arrhenotokous strains of Trichogramma. Qualitative characteristics of parasitoids consisted parasitism rate، adult emergence proportion، longevity، fecundity and number of deformed adults. The results indicated negative effects of host storage time on some qualitative characteristics of T. brassicae. Developmental time، emergence proportion، longevity، fecundity and wing deformity، were under negative influence of host storage time. However، because of different effect of storage on two strains، by selecting suitable strain، there is a possibility to reduce some negative effects.