Effects of herbicides on rice resistance and on multiplication and feeding of brown planthopper (BPH), Nilaparvata lugens (StÅl) (Homoptera: Delphacidae)

Two-way effects of herbicide on rice resistance and multiplication and feeding of the rice brown planthopper (BPH), Nilaparvata lugens (Stål) were studied. Four of 11 herbicides tested, butachlor, metolachlor, oxadiazon and bentazone, had significantly stimulating effects on multiplication and feeding of BPH. Multiplication times (N ₁/N ₀) of BPH on the rice treated with the four herbicides were 674, 367, 322 and 311, respectively, while that of N. lugens on the untreated plants was 159. The results of measurements of honeydew production by BPH indicated that the feeding rates of the brown planthoppers increased when the insects fed on the plants treated with bentazone, quinclorac, oxadiazon and quinclorac. Survival rates of N. lugens first to third-instars rose on the rice plants treated with butachlor, bentazone, but that of the fourth and fifth instars were not affected. Furthermore, all of those herbicides tested led to a decline of rice resistance, i.e. the injury scales of the treated plants were larger than that of the control under the same pest stress. Based on their effects on rice resistance and on BPH, the herbicides tested can be divided into two categories, one affecting rice resistance and BPH multiplication, the other affecting rice resistance only.     

Interaction Effect of Water Magnetization and Water Salinity on Yield,Water Productivity and Morpho-Physiological of Balkız Bean (Phaseolus vulgaris)

Developing new tools for using low-quality irrigation waters is vital for the sustainability of irrigated agriculture and minimizing salt accumulation. Therefore, the present study focused on the interactive influence of irrigation treatments (magnetized (MT) and non-magnetized (NMT)) and water salinities (0.38, 1.5, 4.5, and 7.0?dSm^?1) on soil salinity, water use efficiency, yield and morpho-physiological changes of Balk?z bean. A pot experiment was conducted in a randomized complete block design with three replications under the rain shelter condition. Irrigation water MT treatment increased fresh bean yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE) by 21.35, 23.00 and 14.8%, respectively, while saturated soil salinity was reduced by 20%, compared to NMT treatments. The leaf area, stomata, and leaf succulence in green beans in the MT treatment significantly increased by 13.4, 23.9, and 3.3% compared with those in the NMT treatment. Stems of the bean crops were more sensitive to salinity stress followed by roots and leaves. The study revealed that irrigation with magnetically treated water manages salinity related yield loss through increased morphological features as well as osmotic and stomatal adjustments. In addition, the bean crops showed an ability to protect water in tissue against salinity toxicity up to 5.24?dSm^?1 soil salinity level under magnetized saline water conditions. Finally, irrigation with magnetically treated 0.38?dSm^?1 irrigation water can be recommended due to providing a higher yield, WUE, IWUE, and sustainable production under saline irrigation in water scarcity regions.

     

Effects of short-term low temperatures on photosystem Ⅱ function of samara and leaf of Siberian maple (Acer ginnala) and subsequent recovery

Samara is the reproductive organ (seed) for many tree species in arid land in northwestern China. It is ecologically important in population development due to its dispersal function. However, information on its photosynthesis and effect of environmental stresses on its photosynthesis is still very limited. In the present study, responses of photosystem II (PSII) activity in samara and leaf of Siberian maple to short-term chilling/freezing and subsequent recovery potential were comparatively investigated by using polyphasic fluorescence test. The samara had more efficient photosynthesis (Fv/Fm and PIABS) and more efficient electron transport (φEo) but lower energy dissipation (DIo/RC) than leaf. Generally, the PSII performance and the electron transport for both samara and leaf were inhibited under low temperature stress, accompanied by an increase of energy dissipation in PSII reaction centers (RCs). PSII of both samara and leaf was not markedly affected by chilling and could acclimate to chilling stress. Short-term freezing could completely inhibit PSII activity in both samara and leaf, indicated by the drop of values of Fv/Fm, PIABS, φEo to zero. PSII functional parameters of short-term dark frozen samara could be largely recovered whereas those of frozen leaf could not be recovered. The higher tolerance of samara to short-term low temperature stress than leaf is of great ecological significance for seed development, population establishment of Siberian maple.     

Effects of Cry1Ac toxin of Bacillus thuringiensis and nuclear polyhedrosis virus of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on larval mortality and pupation

In the laboratory, the percentage mortality and pupation of Helicoverpa armigera (Hübner) were investigated when larvae were exposed to Cry1Ac of Bacillus thuringiensis Berliner, nuclear polyhedrosis virus of H. armigera (HaNPV) or Cry1Ac and HaNPV together. The results revealed that interactions between Cry1Ac and HaNPV varied with bioassay method and concentration of the suspension. When larvae were infected using a suspension containing both HaNPV and Cry1Ac, most combinations of Cry1Ac (62.5, 125 and 250 microg mL(-1)) and HaNPV (1.2 x 10(6), 6.0 x 10(6) and 3.0 x 10(7) PIB mL(-1)) showed an antagonistic effect. In the bioassay procedure where larvae were force fed diet containing Cry1Ac 48 h after being infected by HaNPV, interaction between Cry1Ac (0.5, 1, 2, 4 and 8 microg mL(-1)) and HaNPV (6.0 x 10(6) and 3.0 x 10(7) PIB mL(-1)) showed an additive effect, while combinations of Cry1Ac (0.5, 1, 2 and 4 microg mL(-1)) and HaNPV (1.2 x 10(6) PIB mL(-1)) showed an antagonistic effect. In the bioassay procedure where larvae being infected by HaNPV were fed on Cry1Ac diet from neonate to death or pupation, the results suggested that Cry1Ac and HaNPV showed an additive interaction. The percentage mortality was lower in the treatment of larvae infected by transgenic Bt cotton leaf discs containing HaNPV suspension than in the treatment of larvae by conventional cotton leaf discs containing HaNPV, while the pupation rate was higher. The combination of Bt cotton and HaNPV showed antagonism. The present results showed that a combination of Cry1Ac and HaNPV usually resulted in mortality levels greater than in the case of Cry1Ac but not greater than with the virus alone.     

Studies on the biology of Cryphalus piceae (Ratz.) (Coleoptera, Scolytidae) in the Bartin and Karabük regions of Turkey

The purpose of this study is to investigate the biology of Cryphalus piceae (Ratz.) (Col., Scolytidae) living in Abies bornmülleriana (Mattf.) in fir forests in the Western Black Sea region in Turkey. The dates of swarming, tree attack, egg-laying, and different stages of development are given. The species had two generations per year.     

Dissipation of quinalphos (O,O, diethyl O‐quinaxalin‐2yl phosphorothioate) residues in and/or on cauliflower (Brassica oleracea Var. Botrytis)

Abstract

A field trial was conducted to study the magnitude of quinalphos residues in and/or cauliflower (Brassica oleracea Var Botrytis. The cauliflower crop was sprayed once with quinalphos 25 e.c. at 0.25 and 0.5 kg a.i./ha 104 days after transplanting. The samples of cauliflower drawn at different time intervals were analysed colorimetrically. The initial deposits of quinalphos on cauliflower were found to be 5.79 and 9.52 ppm, an the half life values 1.61 and 2.12 days, respectively, at 0.25 and 0.5 kg a.i./ha. The waiting periods determined were 11 days at the higher and 7 days at the lower dose of quinalphos.     

Effect of pre‐storage seed treatments on adult mortality,oviposition and development of Callosobruchus chinensis L. (Bruchidae: Coleoptera), and the viability of mungbean (Vigna radiata (L.) Wilczek) in India

Abstract

The adult mortality of Callosobruchus chinensis L. was 100% within 24 h after artificially infesting seeds pretreated with inert clay and stored for 12 months under ambient conditions. Pre‐treatment with thiram and delsan‐30 (TCMTB) were also effective in controlling the adults by impairing oviposition. The seeds maintained over 80% germination up to 12 months of storage under all the treatments.     

Males of Ichthyofilaria argentinensis Incorvaia, 1999 and I. bergensis (Wülker, 1930) (Dracunculoidea:Guyanemidae): new morphological aspects and emendation of the generic diagnosis

Abstract: The adult male of dracunculoid nematode Ichthyofilaria argentinensis Incorvaia, 1999 (Guyanemidae) is described for the first time based on specimens found in the swimbladder of its type host, Merluccius hubbsi Marini (Merlucciidae), caught off the coast of Buenos Aires, Argentina (western Atlantic Ocean). In addition, the males of Ichthyofilaria bergensis (Wülker, 1930) K?ie, 1993 are redescribed from specimens collected from the body cavity and visceral surface of Molva macrophthalma (Rafinesque) (Lotidae) caught in the western Mediterranean Sea, off the coast of Sardinia. Light and scanning electron microscopy examinations revealed some new morphological features for the genus, such as a pair of deirids located near the end of muscular oesophagus, the body wall conspicuously twisted immediately anterior to the cloaca, the presence of a copulatory plate, one pair of adcloacal papillae and a pair of phasmids situated on the posterior half of the tail. On the basis of this material, the generic diagnosis of Ichthyofilaria is modified to include some of these newly observed features, as well as to indicate the absence of spicules. The diagnosis of Guyanemidae is extended to include that a copulatory plate and/or two spicules may be present as characteristics for this family.     

Effectiveness of two insect growth regulators against Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and their impact on population densities of arthropod predators in cotton in Pakistan

Field efficacies of two insect growth regulators (IGRs) at two recommended application rates, buprofezin at 370 and 555 g AI ha(-1) and lufenuron at 37 and 49 g AI ha(-1), were determined against the sweet potato whitefly, Bemisia tabaci (Gennadius), and the cotton bollworm, Helicoverpa armigera (Hübner), in experimental plots of cotton at the Directorate of Cotton Research, Faisalabad, Pakistan. Adverse effects of the IGRs on populations of associated arthropod predators, namely geocorids, chrysopids, coccinellids, formicids and arachnids, were also assessed. Both IGRs significantly reduced populations of B. tabaci at each application rate 24, 48 and 72 h after treatment, and higher doses were more effective than lower doses. Buprofezin was not effective against H. armigera at any tested dose for any time of treatment in any spray. Lufenuron applied at 37 and 49 g AI ha(-1) effectively suppressed H. armigera populations, resulting in significant reductions in crop damage. At lower doses, both IGRs appeared safe to predator populations, which did not differ significantly in IGR-treated versus untreated control plots. Population densities of formicids and coccinellids were significantly lower at high concentrations of both IGRs in treatment plots, possibly as a result of reduced prey availability. The potential role of buprofezin and lufenuron for control of B. tabaci and H. armigera in a spray programme and the likelihood of direct toxic effects of IGRs on predatory fauna of cotton are discussed.     

Evaporative enrichment of stable isotopes(δ~(18)O and δD) in lake water and the relation to lake-level change of Lake Qinghai,Northeast Tibetan Plateau of China

Stable isotopic compositions(δ18O and δD) have been utilized as a useful indicator for evaluating the current and historical climatic and environmental changes. Therefore, it is vital to understand the relationship between the stable isotopic contents in lake water and the variations of lake level, particularly in Lake Qinghai, China. In this study, we analyzed the variations of isotope compositions(δ18O, δD and d-excess) in lake water and precipitation by using the samples that were collected from Lake Qinghai region during the period from 2009 to 2012. The results showed that the average isotopic contents of δ18O and δD in lake water were higher than those in precipitation, which were contrary to the variations of d-excess. The linear regression correlations between δ18O and δD in lake water and precipitation showed that the local evaporative line(LEL) in lake water(δD=5.88δ18O–2.41) deviated significantly from the local meteoric water line(LMWL) in precipitation(δD=8.26δ18O+16.91), indicating that evaporative enrichment had a significant impact on isotopic contents in lake water. Moreover, we also quantified the E/I ratio(evaporation-to-input ratio) in Lake Qinghai based on the lake water isotopic enrichment model derived from the Rayleigh equation. The changes of E/I ratios(ranging from 0.29 to 0.36 between 2009 and 2012) clearly revealed the shifts of lake levels in Lake Qinghai in recent years. The average E/I ratio of 0.40 reflected that water budget in Lake Qinghai was positive, and consistent with the rising lake levels and the increasing lake areas in many lakes of the Tibetan Plateau. These findings provide some evidences for studying the hydrological balance or water budget by using δ18O values of lake sedimentary materials and contribute to the reconstruction of paleolake water level and paleoclimate from an isotopic enrichment model in Lake Qinghai.     

Effects of irrigation on the performance of cotton bollworm,Helicoverpa armigera (Hübner) during different pupal stages

Pupation of cotton bollworm, Helicoverpa armigera (Hübner), occurs in the soil. This may be a weak link in the life-cycle, exploitable through cultivation, in the control of this important pest. We evaluated the effects of irrigation on the performance of H. armigera. It did not affect the numbers of larvae entering the soil. However, irrigation treatments made on the 2nd, 3rd and 10th day after larvae entered the soil significantly reduced moth emergence (27, 19 and 28.7% emerged from the respective treatments, compared to 93.7% emerging from the control). Irrigation did not affect the time taken from the larva entering the soil to female adult emergence, but it significantly delayed the time in males. Realized fecundity of the emerging H. armigera adults was significantly decreased by irrigation treatment, especially on the 10th day, with a mean of only 367 eggs laid per female. Irrigation after larvae entered the soil substantially decreased survival of H. armigera, and the increase in the size of the generation following irrigation was only 2.8 times for the irrigation treatments on the 3rd and 10th day after larva entered the soil, respectively, compared with that of the control treatment. We suggest utilizing irrigation practices to suppress overwintering pupal numbers, in order to control the spring generation of H. armigera.     

Gamma radiation sensitivity of the eggs, larvae and pupae of Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

BACKGROUND: This study focused on determining the minimal effective gamma radiation dose that prevents commodity damage caused by the Indian meal moth Plodia interpunctella (Hübner). The study was also designed to assess the effect of releasing either partially sterilized males alone or both partially sterilized males and females on the reproductive potential of P. interpunctella populations. RESULTS: The dose of radiation required to prevent larval emergence from irradiated eggs was 350 Gy, and the same dose was also required to prevent adult emergence from mature larvae. A dose of 300 Gy was not able to prevent adult emergence from irradiated pupae. The dose at which 100% sterility was achieved in treated females mated to treated males was 300 Gy for the parental generation of irradiated pupae. Fertility of the parental males from irradiated pupae was 48.17% at 300 Gy in treated males crossed with untreated females, but male progeny of irradiated male parents had a residual fertility of 11.06% at the same dose. CONCLUSION: F(1) males from irradiated pupae were more sterile than parental males. To prevent larval emergence from irradiated eggs, a dose of 350 Gy is required. The same dose is required to prevent the larvae from reaching the adult stage.     

Coexpression with Auxiliary β Subunits Modulates the Action of Tefluthrin on Rat Na(v)1.6 and Na(v)1.3 Sodium Channels

The erythrocyte, due to its role as O₂ and CO₂ transporter, is under the constant exposure to reactive oxygen species and oxidative stress. The objective of this study was to investigate the ability of 2,4-D to induce oxidative stress in blood of male wistar rats. Rats were randomly divided into four groups: a control group and three treated groups receiving by gavage 15, 75 and 150 mg, respectively, of 2,4-D/kg/BW/day for 28 days. Results showed that 2,4-D caused significant negative changes in the investigated biochemical parameters. In fact, 2,4-D exposition strongly increases LDH, by contrast, there is a statistically significant decrease in Hgb levels. The malondialdehyde level was significantly increased in 2,4-D treated groups. Fatty acid composition of the erythrocytes was also significantly changed with 2,4-D exposure, in favor of the peroxidation of polyunsaturated fatty acids. Furthermore, antioxidant enzyme (SOD, CAT, GPx, and GR) activities in erythrocytes were significantly decreased. Thus, our results indicated the potential effects of 2,4-D to cause oxidative stress in rat erythrocytes. Therefore, at higher doses, 2,4-D may play an important role in the development of vascular disease via lipid peroxidation and oxidative stress.     

Morphological, anatomical and molecular investigation into witches’ broom disease of mamejvo (Enicostemma axillare)

Mamejvo (Enicostemma axillare Raynal) is a perennial herb with diversified health benefits. It was found to be affected by a witches?? broom disease under the field conditions at Anand, Gujarat, India. Affected plants were 53.33% reduced in height due to shortened internodes, leading to typical witches?? broom symptoms. Flower size was reduced significantly in the affected plants compared with the healthy ones and their petal color gradually turned green (virescence). Affected plants produced 2.5 times more dry herbage than the normal plants but with less active ingredient (swertiamarin). Symptomatic plants died early while root suckers from such plants failed to establish after transplanting. DAPI stained transverse sections of affected shoot tips showed the presence of discrete greenish fluorescence in the phloem cells under UV light. Amplification of 1.2?kb phytoplasma specific rDNA fragment from diseased tissue confirmed the presence of the pathogen. Further characterization of the pathogen through virtual rDNA?CRFLP pattern and rDNA sequence based phylogeny suggested that the pathogen, Enicostemma witches?? broom phytoplasma, belonged to 16SrII?CC group of ??Ca Phytoplasma aurantifolia??.     

Sub-lethal influences of different insecticides on oviposition preference of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on cotton in relation to altered plant morphology

We investigated the sub-lethal influences of spinosad, chlorpyriphos, endosulfan, acephate and cypermethrin on the oviposition responses of Helicoverpa armigera (Hübner) to cotton plants, under cage and laboratory conditions. The rank order of toxicity (LC₅₀ values as a per cent) of test insecticides against third instar larvae using the leaf disc method was: spinosad > chlorpyriphos > endosulfan > acephate > cypermethrin. On whole plants, females laid more eggs on acephate LC₅₀-, acephate LC₃₀- and cypermethrin LC₅₀-treated cotton plants than on the control. The chlorpyriphos-treated plants were least preferred for oviposition. When excised cotton leaves from different treatments were used in a multiple-choice test, cypermethrin LC₅₀- and endosulfan LC₃₀-treated leaves received more eggs than the control. The repeated application of sub-lethal concentrations of different insecticides reduced plant height in the case of acephate LC₃₀ and cypermethrin LC₅₀, while plant spread and upper canopy leaf area were reduced in both treatments of acephate and cypermethrin. Reduced plant spread, upper canopy leaf area followed by plant height were found associated with oviposition preference by H. armigera females.     

Effect of α tocopherol and selenium on antioxidant status, lipid peroxidation and hepatopathy induced by malathion in chicks

The objective of the present study was to investigate the role of α tocopherol and selenium on malathion induced hepatic damage, and antioxidant defense in chicks. The chicks were divided into three groups. First group received malathion 10 mg/kg BW, orally for 60 days, the second group received the same dose of malathion but was supplemented with α tocopherol and selenium for 60 days and the third group served as the control. A compromised antioxidant capacity as evidenced by increased levels of erythrocytic lipid peroxidation and decreased concentration of vitamin E and decreased activity of glutathione peroxidase was observed in chicks following the administration of malathion. An improved antioxidant status was observed in chicks of second group with α tocopherol and selenium supplementation including higher concentration of vitamin E, increased activity of glutathione peroxidase and lower levels of lipid peroxidation. Histopathological studies of liver in the chicks which received malathion exhibited, moderate to severe degenerative and necrotic changes in the hepatocytes. The correlation of decreased antioxidant status of chicks with degenerative changes in liver suggests that lipid peroxidation may be one of the important mechanism in the chronic toxicity of malathion. The results indicate that α tocopherol and selenium were effective in partially alleviating degenerative changes induced by malathion in the liver of chicks by attenuating processes leading to lipid peroxidation.