Effect of host plants on fitness traits and detoxifying enzymes activity of Helopeltis theivora, a major sucking insect pest of tea

Helopeltis theivora Waterhouse (Heteroptera: Miridae) is a major sucking insect pest of tea (Camellia sinensis) which feeds on a wide variety of alternative host plants. Feeding biology and fitness traits of H. theivora, on two alternative host plants, viz., Mikania micrantha (Asteraceae) and Psidium guajava (Myrtaceae), besides C. sinensis (Theaceae), were studied along with corresponding levels of xenobiotic defense enzymes. C. sinensis is the preferred host of H. theivora. The development time of H. theivora is significantly shorter on C. sinensis (13.3?±?0.16?days) than on the two other hosts, M. micrantha (14.2?±?0.22?days) and P. guajava (14.7?±?0.23?days). Similarly, the fecundity (C. sinensis: 172.6?±?4.5 eggs/female, M. micrantha: 128.6?±?4.4 eggs/female, P. guajava: 118.7?±?3.3 eggs/female), oviposition period (C. sinensis: 24.1?±?0.7?days, M. micrantha: 22.5?±?0.6?days, P. guajava: 21.7?±?0.8?days) and hatchability (C. sinensis: 80.9?±?1.9%, M. micrantha: 69.4?±?1.6%, P. guajava: 64.1?±?1.7%) are recorded to be significantly higher on C. sinensis. The age at reproductive maturity and egg incubation periods were lower on C. sinensis than on the two other host plants. Host-based variation in H. theivora fitness traits is interpreted in light of differential activity of three principal xenobiotic detoxifying enzymes, the general esterases (GEs), glutathione S-transferases (GSTs) and cytochrome P450 monooxygenases (CYPs). The activities of these enzymes in H. theivora were significantly enhanced when the insect fed on M. micrantha and P. guajava as compared with on C. sinensis.     

Life table and some feeding features of Nephus kreissli fed on Planococcus ficus

In this study certain biological and prey consumption features of the predator of mealybug, namely Nephus kreissli Fürsch & Uygun (Coleoptera: Coccinellidae), fed on vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were determined under the laboratory conditions. Experiments were performed in the acclimatized room under 28?±?1°C, 60?±?10% r.h. and a photoperiod of 16:8 h(L:D) conditions. To determine the biological features of the coccinellid, predator individuals were continuously observed from egg stage to end of adult stage. The development, survival and fecundity of N. kreissli were determined and all the measured data were recorded daily. The total development time from egg to the eclosion of adult stage was determined as 31.6?±?0.4 days. The lifespan of males and females was 66.0?±?3.8 and 65.8?±?3.5 days, respectively; and a single female laid 122.6 eggs. The raw data related to life history were analyzed by using the age-stage, two-sex life table. The intrinsic rate of increase, the net reproductive rate, and the mean generation time were 0.0709?±?0.0036 d^?1, 53.1?±?9.5 offspring and 55.8?±?1.3 days, respectively. The first and second instars of N. kreissli preferred egg stages of P. ficus to other stages of mealybug. On the other hand, third and fourth instars and adult predators preferred the second and third instar nymphs and adult females of the prey. It was determined that the egg consumption of N. kreissli increased with the development of larval stages, and that the highest consumption was recorded in its fourth instar.     

Effect of <Emphasis Type="Italic">Metarhizium guizhouense</Emphasis> infection on mating competition and mate choice of <Emphasis Type="Italic">Bactrocera latifrons</Emphasis> (Diptera: Tephritidae)

Metarhizium guizhouense PSUM02 treated males of Bactrocera latifrons were investigated for the mating competition among males and mating choice by female flies to develop an auto-dissemination for the control of B. latifrons. In the present study, on day 1–4 of experiment, M. guizhouense–treated male flies were equally competitive with the normal male flies as we did not observe any differences in mating by treated and normal male flies of B. latifrons. Further, mating competitiveness were found low in treated adult male B. latifrons than normal male B. latifrons from 5th days of treatment until death. Kaplan-Meier survival analysis of treated male flies gave average survival times (AST) of 4.3?±?0.1 days, while the healthy female and male flies in the same cage showed AST of 9.3?±?0.3 and 8.3?±?0.4 days, respectively. The AST of untreated flies in control experiment ranged from 14.2–14.5 days. In mating preference experiment, M. guizhouense–treated male flies were chosen by virgin female than gravid female flies for mating. The treated male flies caused mortality in both virgin and gravid female flies in the same cage with AST of 4.4?±?0.1, 5.6?±?0.1 and 7.4?±?0.2 days, respectively, while untreated flies showed AST ranged from 13.9–14.3 days in control. The treated male flies could transmit the fungus infection to both untreated female and male flies as well as in virgin and gravid female flies by mating and contact. Our experiments showed the potentiality of M. guizhouense PSUM02 in management of B. latifrons by auto-dissemination with treated male flies, which transmit the fungus to a healthy population to reduce insect pest infestations.     

Frequency distribution of sensitivity of Ustilaginoidea virens to four EBI fungicides, prochloraz, difenoconazole, propiconazole and tebuconazole, and their efficacy in controlling rice false smut in Anhui Province of China

False smut, caused by Ustilaginoidea virens, is an important emerging disease of rice (Oryza sativa L.) in China. Up to now, as most varieties with high yielding and good quality are susceptible or even highly susceptible to false smut in most rice-growing ecological regions, especially in Anhui Province, chemical control with fungicides would be an important measure for the control of this disease. The ergosterol biosynthesis inhibitor (EBI) fungicides, such as prochloraz, difenoconazole, propiconazole and tebuconazole, are extensively used in China for the control of rice diseases, such as rice sheath blight and rice blast. In this study, a total of 102 U. virens isolates (from Anhui Province of China) were tested for their sensitivity to these four EBI fungicides during the stage of mycelial growth. The EC₅₀ ranges of values for prochloraz, difenoconazole, propiconazole and tebuconazole inhibiting mycelial growth of the 102 U. virens isolates were 0.04–0.75, 0.04–1.08, 0.04–0.38 and 0.03–0.57 μg?ml^?1, with the average EC₅₀ values of 0.32?±?0.08, 0.45?±?0.08, 0.19?±?0.03 and 0.21?±?0.06 μg?ml^?1, respectively. These values suggested that the tested U. virens isolates were very sensitive to these four EBI fungicides. Results of field trials showed that two sprays of three of the fungicides exhibited greater control efficacy than a single spray for the control of rice false smut. Two sprays of each was better than a single spray for the control of rice sheath blight. Two sprays of 50% propiconazole EC at 300 g a.i. ha^?1 gave the best control of rice false smut at both two sites during the two consecutive years, 2010 and 2011, with the control efficacy ranging from 71.5 to 74.3%. Sensitivity of the field U. virens isolates to EBI fungicides should be monitored. Mixtures, as well as alternation with other fungicides with different modes of action, should be tested.     

Biology and seasonal abundance of the two-spotted spider mite, Tetranychus urticae, on orchids and rose

Biology of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) was studied on five orchids and one rose species under laboratory conditions. The duration of developmental stages of this mite was the shortest on rose (7.17 ± 0.20 days) followed by Cymbidium (10.49 ± 1.50 days), Oncidium (11.60 ± 1.32 days), Dendrobium (12.67 ± 0.21 days), Phalaenopsis (14.47 ± 1.21 days) and Coelogyne (17.10 ± 1.29 days). The number of eggs/female laid was maximum on rose, whereas the minimum was on Phalaenopsis under the most suitable temperature (26 ± 2°C) and relative humidity (65 ± 5%) conditions. The five orchid farms (three conventionally sprayed and two unsprayed) in the northeastern region of India were surveyed during 2009 and 2010 for mite incidence. Twenty-three species and 11 hybrids of orchids were encountered as the most preferred host, 12 species as moderately preferred, and 28 species and one hybrid were found to be the least preferred orchid host for T. urticae. The mite’s incidence was recorded on orchids all year round, indicative of overlapping generations; however, two distinct population peaks were recorded during April and May. Subsequently its population declined at the start of the rainy season and remained at extremely low levels in the winter. Maximum and minimum temperatures had a significant positive correlation with mite incidence; daylight had a non-significant positive correlation; and rainfall and relative humidity had non-significant negative correlations with mite incidence. The results are discussed in relation to the most susceptible stage on orchids and suitable management practices for the two-spotted spider mite in India.     

Influence of abiotic factors on behaviour and adult emergence pattern of coconut white grub, <Emphasis Type="Italic">Leucopholis coneophora</Emphasis> Burmeister (Coleoptera: Scarabaeidae)

Leucopholis coneophora Burmeister is a subterranean pest associated with coconut based cropping systems in south India. Feeding damage causes yellowing of fronds and yield reduction. To develop appropriate IPM strategy a basic knowledge on insect behaviour is essential. Four years studies indicated that, adult emergence of L. coneophora was commenced with summer shower in April in Kerala. Delay in summer shower delayed the emergence. After a pause in May, the emergence resumed with the setting of south west monsoon in June. The beetles did not emerge during dry spells in between the rainy days, when the soil temperature (at 10 cm depth) was ≥34.5 °C. Emergence of the beetles started at an illuminance of 124.37?±?75.5 l in evening and remained active till 2?±?0.4 l with a maximum swarming at 32.6?±?15.1 l. Female emergence and mating occurred at 12.04?±?8.1 l. Female based sex pheromone mediated communication is evident. Strong competition among the males for mating with emerging female, which was evident by a wider operational sex ratio in the initial period (1:10.11) that narrowed down to 1:4.33 in later days. The beetles neither congregate on any host plant nor exhibit phototaxis. Number of beetles entrapped in light traps varied from 1.5–16.5% and hand picking is highly significant over light trapping. Hence hand picking of beetles daily in the evening for 2 weeks commencing from the onset of south west monsoon in Kerala, in Indian subcontinent is suggested as a tool in IPM.     

Host status of cultivated plants to <Emphasis Type="Italic">Meloidogyne hispanica</Emphasis>

The reproduction of a Meloidogyne hispanica isolate from Portugal was evaluated in 63 plant species/cultivars, in pot assays at 25?±?2.0°C, on the basis of root gall index (GI) and reproduction factor (Rf?=?final/initial egg density) at 60 days after inoculation. Cultivars of aubergine, bean, beetroot, broccoli, carnation, corn, cucumber, French garlic, lettuce, melon, onion, parsley, pea, potato, spinach, and tobacco and two of cabbage were susceptible (3?≤?GI?≤?5; 1.15?≤?Rf?≤?262.86). Cabbage cv. Bacalan, cauliflower cv. Temporão and pepper cv. Zafiro R2 were hypersusceptible or poor hosts (Rf??2) and pepper cvs. Aurelio and Solero were resistant (0.0?≤?GI?≤?0.4; 0.00?≤?Rf?≤?0.03). The response of the pepper cultivars and the Mi-1 resistant tomato cv. Rossol was also conducted in pots using two inoculum levels and four temperatures, three growth chamber (25?±?2.7°C, 29.3?±?1.8°C and 33.6?±?1.2°C) and one outdoors (24.4?±?8.2°C). At 24.4?±?8.2°C and 25?±?2.7°C, the reproduction on the resistant tomato was significantly lower compared to the susceptible cv. Easypeel. At all temperatures, resistance was evident for the pepper cultivars, despite the fact they were not found to contain any of the Me1, Me3, Me7 and N genes. The eggs obtained on cv. Aurelio at 33.6?±?1.2°C were used to get a selected resistance breaking isolate of M. hispanica that was able to reproduce on the three pepper cultivars. Our results suggest that the initial M. hispanica isolate is a mixture of virulent and avirulent individuals. The pepper cultivars tested, have potential to reduce M. hispanica populations in agro-ecosystems under certain conditions, but they should be used as a part of an integrated management strategy in order to prevent the development of virulent populations.     

Multi-resistance to thiophanate-methyl,diethofencarb, and procymidone among <Emphasis Type="Italic">Alternaria alternata</Emphasis> populations from tobacco plants,and the management of tobacco brown spot with azoxystrobin

In 2014 and 2015, a total of 151 tobacco brown spot (Alternaria alternata) isolates were collected from Guizhou Province in China to evaluate their resistance to the benzimidazole thiophanate-methyl, the carbamate diethofencarb, and the dicarboximide procymidone. Resistance to thiophanate-methyl and diethofencarb was observed in all isolates. Resistance to all the three fungicides, thiophanate-methyl, diethofencarb, and procymidone was detected at a frequency of 6.0%. The F167Y single mutation in the β-tubulin gene was found to be associated with resistance to thiophanate-methyl,but no mutation was found in the coiled-coil region of the histidine kinase-encoding gene OS1, a fungal gene for dicarboximide resistance. Procymidone applied at the rate of 20 mg l^?1 inhibited spot lesion formation on tobacco leaves with an efficacy of 51.7% for the low resistance (LR) isolates and 74.2% for the procymidone-sensitive isolates. Thiophanate-methyl applied at 100 mg l^?1, however, slightly promoted the expansion of disease lesions with an efficacy of ?7.7%. Azoxystrobin applied at 10 and 20 mg l^?1 provided efficacies of 91.1 and 100%, respectively, regardless of whether the isolates were thiophanate-methyl resistant or procymidone-LR. Further studies suggested that azoxystrobin exhibited excellent protective activity and good curative activity against A. alternata in plants. The baseline sensitivity to azoxystrobin was then determined. In the presence SHAM, the mean EC₅₀ values for conidial germination inhibition were 0.49?±?0.22 (Mean?±?SD) mg l^?1. Interestingly, no resistance was recovered through UV irradiation or Agrobacterium tumefaciens-mediated mutagenesis. This research indicated widespread resistance to thiophanate-methyl and diethofencarb, low frequency of (6.0%) resistance to procymidone in A. alternata populations from tobacco, and suggested that azoxystrobin could potentially constitute a good alternative for the management of tobacco brown spot disease.     

Development of <Emphasis Type="Italic">Tetranychus ludeni</Emphasis> (Acari: Tetranychidae) on transgenic soybean cultivars

The aim of this study was to assess the influence of transgenic soybean [Glycine max L. (Fabaceae)] cultivars on the biological cycle of Tetranychus ludeni Zacher (Acari: Tetranychidae) in laboratory conditions. We used three cultivars: a conventional soybean (CO), a glyphosate-resistant with insertion of genes of Agrobacterium sp., Roundup Ready (RR), and a glyphosate-resistant with insertion of genes of Bacillus thuringiensis var. israelensis (BT). Duration of developmental stage, mite viability, number of laid eggs, and female longevity of T. ludeni were evaluated. The duration of the deutonymph phase was shorter in RR (2.1?±?0.12 days) than in CO (2.6?±?0.12) and BT (2.5?±?0.08). The duration of egg, larval, and protonymph phases were similar for T. ludeni on the three cultivars. The mean duration of each generation (T), net reproduction rate (R_o), intrinsic rate of natural increase (r_m), and doubling time (DT) were similar on the three cultivars. Results showed that population growth are not influenced by transgenesis at the laboratory level. Females died without a post-oviposition period on all soybean cultivars. The intrinsic rate of natural increase of T. ludeni on soybean cultivars was low (between 0.15 and 0.17).     

Variability in the sensitivity of biotrophic grapevine pathogens (Erysiphe necator and Plasmopara viticola) to acibenzolar-S methyl and two phosphonates

The antifungal properties of two phosphonates (fosetyl-Al and a fertilizer) and acibenzolar-S-methyl (ASM) were evaluated to assess their potential for protecting grapevine leaves against grapevine mildews (Plasmopara viticola and Erysiphe necator), and to determine their effects on the development of various mildew isolates, taking into account the inter- and intra-species variability of the pathogens. The phosphonates directly and significantly inhibited the growth of these pathogens. By contrast, ASM had no direct effect on spore production and growth of P. viticola and of E. necator at 1.9 mM. Applied before inoculation, the mean EC₅₀ of ASM was 0.50?±?0.04 mM and 1.00?±?0.07 mM for downy and powdery mildew isolates, respectively. The EC₅₀ of the fosetyl-aluminium (FOS) was 0.50?±?0.02 mM for downy mildew and the EC₅₀ for powdery mildew varied depending on the genetic group under consideration (0.89?±?0.32 mM for group B 3.30?±?0.46 mM for group A, respectively). The EC₅₀ of the potassium phosphonate fertilizer (PK₂) was 0.96?±?0.45 mM for downy and 6.9?±?0.76 mM for powdery mildew isolates. These compounds showed differences in their efficacy depending on the variability of mildews and could be an alternative or additional method to traditional pest management in the grapevine.     

Unusual behavior of oviposition and development of <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> (Coleoptera: Curculionidae) in peach and apple fruits

The maize weevil Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) is a worldwide pest on stored products, as maize, wheat and rice grains. However, in South Brazil, these weevils have been found attacking fruits in field conditions. It was reported that adults attack fruits to feeding, but there was no information of oviposition and larval development on these hosts. Furthermore, due to monitoring apple orchards, was observed that some fruits showed distinct kind of punctures, suggesting a oviposition by these weevils. The present study reports first record an unusual behavior of S. zeamais by oviposition and larval development in peach and apple fruits. The study was conducted in laboratory conditions (temperature: 25?±?1 °C, RH: 70?±?10% and photophase of 14 h). Peach and apple fruits were offered to S. zeamais females. The oviposition and duration of immature stages in peach were measured in fruits and in corn grains, used as control observation. The oviposition and larval development occurred in peach and apple fruits, with a development until to adult. The average of egg-to-adult was 47.4 d in peach and and 45.1 d apple fruits, respectively, while in corn grains, its natural host, the duration was 38.2 d. These results show that the damage caused by S. zeamais in peach and apple fruits may be due to oviposition and the development of immature stages. So, the novelty is in demonstrating that the maize weevil does not just feed as an adult opportunistically on the fruits, but can complete a full life cycle using fresh fruits.     

Nematicidal activity of some essential plant oils from tropical West Africa

Abstract

Plant parasitic nematodes are among the most destructive plant pathogens worldwide and their control is very challenging. Plant essential oils (EOs) have showed a great potential in nematode control. In this work, EOs from 10 aromatic plants acclimatized in Togo were assessed in vitro for their nematicidal activity on the root-knot nematode Meloidogyne incognita. EOs were subsequently analyzed by GC-MS and compounds were tested individually on nematodes. The most potent EOs were: Ocimum sanctum L., Cymbopogon schoenanthus (L.) Spreng and Cinnamomum zeylanicum Blume with EC_50/72h values of 282?±?53, 288?±?30 and 355?±?126?mg/L, respectively. The EC_50/48h values of tested compounds were 81?±?14, 117?±?33, 128?±?42, 141?±?47, 168?±?40, 216?±?86 and 235?±?43?mg/L for cinnamyl acetate, methyl eugenol, cinnamyl alcohol, acetyl eugenol, isoeugenol, eugenol and benzyl benzoate, respectively. Furthermore, we found a synergistic nematicidal activity when we combined phenylpropanoids compounds with carvone. EOs and their constituents described herein merit further studies, especially in pot experiments before serving as nematicides.     

Effects of plant residue management on soil properties,surface runoff,and soil loss under rainfall simulation in a semi-arid region in Iran

A 5-year field study was conducted on the effect of plant residue management on soil erosion, runoff, bulk density, penetration resistance, and organic carbon. There were three treatments: burning residues on field (BR), returning residues unto the soil surface after harvesting (TR), and removing residues from soil surface (RR) (control treatment). At the end of the 5-year treatment, a rainfall simulation at 90?mm?h^?1 was applied to each plot. After rainfall simulation started, the runoff volume and soil loss amount in samples were collected at four sampling times. The results showed that the runoff volume for BR (from 145.5?±?12.2 to 190.0?±?11.8?mL) differed significantly (p?≤?0.01) from that of RR (from 32.3?±?5.5 to 67.5?±?11.1?mL) and TR (from 10.0?±?0.7 to 16.7?±?3.3?mL). A significant difference (p?≤?0.01) was also observed between RR and TR regarding runoff volume and soil loss amount in different sampling times, except for the first sampling time (2–4?min). The runoff volume in BR and TR was 215% higher and 294% lower than that of the control (RR), respectively. As compared to the control (RR), soil loss decreased by 96.5% in TR but increased by 192% in BR. The BR increased soil bulk density and penetration resistance by 4.9% and 12.4%, whereas TR reduced them by 2.1% and 15.8%, respectively, as compared to the control (RR). The results indicated that the highest (0.35) and lowest (0.03) runoff coefficients were obtained for BR and TR treatments, respectively. It is concluded that returning plant residues to soil is the best residue management practice in decreasing soil runoff volume and controlling soil erosion in semi-arid regions.     

Photolytic versus microbial degradation of clomazone in a flooded California rice field soil

BACKGROUND: Clomazone is a popular herbicide used on California rice fields and exhibits rapid anaerobic microbial degradation (t_1/2 = 7.9 days). To test the potential of direct and indirect photolytic degradation as a cofactor in the overall degradation rate, sacrificial time‐series microcosms were amended with water, non‐sterilized soil + water and sterilized soil + water. Clomazone was added to each microcosm, which was then exposed to natural and artificial sunlight over 35 days. Water and acetonitrile extracts were analyzed for clomazone and metabolites via LC/MS/MS. RESULTS: The calculated pseudo‐first‐order degradation rate constants (k) were k_water = 0–0.005 ± 0.003 day^?1, k_sterile = 0–0.005 ± 0.003 day^?1 and k_non?sterile = 0.010 ± 0.002–0.044 ± 0.007 day^?1, depending on light type. The formation of ring‐open clomazone, a microbial metabolite, correlated with clomazone degradation. Trace amounts of 5‐hydroxyclomazone (m/z = 256 → 125), aromatic hydroxyclomazone (m/z = 256 → 141) and an unknown product (m/z = 268 → 125) were observed. CONCLUSIONS: The photolytic degradation rate depends on both light type and the quality of the chromophores that induce indirect photolysis. Microbial degradation was found to be sensitive to temperature fluctuations. Overall, microbes are shown to be more detrimental to the environmental fate of clomazone than photolysis. Copyright © 2012 Society of Chemical Industry     

Ground-active arthropod response to distance from the Mediterranean seashore in coastal sand areas of western Israel

Information on the effects of distance from the seashore on soil biotic communities is limited and restricted to soil arthropods and microarthropods. The aim of this study, conducted in a sand-dune area, was to distinguish the changes of a ground-active arthropod community along a 4-km-transect from the seashore going inland. Pitfall traps were set up in open spaces at four locations (L1, through L2, L3, and L4 going inland) through the year. The abiotic gradient from the seashore going inland was found to be mostly dependent on seasonality. Group richness was found to be remarkably greater at the L2, L3, and L4 locations compared with the L1 location in winter, and at the L2 and L3 locations compared with the L1 location in spring. The Fisher α index was 0.32?±?0.21, 3.51?±?0.87, 5.04?±?0.70, and 4.86?±?0.54 in winter and 3.29?±?0.55, 13.79?±?1.49, 10.12?±?1.24, and 5.06?±?0.62 in spring at the L1, L2, L3, and L4 locations, respectively. Regarding abundance and group richness, the trophic relationships between predators, phytophages, omnivores, and saprophages were remarkably affected by both location and seasonality. The dominant groups and dominant index distribution of ground-active arthropod communities were found to follow a similar pattern. Soil organic carbon content was found to be the key factor driving the ground-active arthropod community structure along a coastal gradient going inland in winter and spring. We conclude that the distribution, trophic composition, and diversity index are affected by both location and seasonality, while total abundance is consistently affected by location across all three seasons.     

Challenging the larvae of <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> and assessing the immune responses to nematode-bacterium complex

Helicoverpa armigera is a strong insecticidal resistance developed insect pest. The understanding of its innate immune responses to emerging biocontrol agent entomopathogenic nematode-bacterial complex can provide an opportunity to control this insect in an environmentally benign manner. Study was focused on role of hemocytes changes and PO activity in Steinernema abbasi-Xenorhabdus indica challenged larvae of H. armigera over the time. Total cell count changed effectively from 10.2?±?1.81?×?10⁵ to 15.5?±?3.3?×?10⁵ cells/mm³ upto 9 h and reduced distinctly up to 8.0?±?2.49?×?10⁵ cells/ mm³ in 24 h. PO activity inclined significantly and was recorded highest at 9 h (24.67?±?1.08?×?10² units) and lowest at 24 h (14.34?±?0.74?×?10² units) in total hemolymph with a similar pattern in plasma and the cellular fraction. Phenoloxidase activity in total and cellular component of hemolymph was positively correlated with prohemocytes, granulocytes and oenocytoids. Study showed the hemocytes and PO accounted as active immune responses against nematode infection. The results provide the first insight to understand the hemolytic activity, quick immunosuppression responses of S. abbasi-X. indica and vulnerability of H. armigera.     

Experimental transmission of the mild strain of Tomato yellow leaf curl virus (TYLCV) to Amaranthus dubius by Bemisia tabaci

Tomato yellow leaf curl virus (TYLCV) is a monopartite begomovirus from the Old World. The mild strain of this virus (TYLCV-Mld) was described for South America in Venezuela in 2007. Due to the potential risks of establishment of this virus in the field, six common weeds were evaluated for susceptibility to an isolate of TYLCV-Mld by using adults of Bemisia tabaci (Hemiptera: Aleyrodidae) to mediate viral transmission. In this work, detection based on PCR amplification with TYLCV specific primers showed Amaranthus dubius (Amaranthaceae) as the only infected weed. In A. dubius, viral symptoms were observed from 11.0?±?1.3?days post-inoculation and the transmission rate of TYLCV-Mld to this plant species was 83.3%. The successful back-transmission of TYLCV-Mld from A. dubius to tomato plants was demonstrated.     

Spatial distribution of wind-driven sediment transport rate in a fallow plot in Central Anatolia,Turkey

Wind erosion is a serious land degradation phenomenon in semi-arid parts of Turkey. It is even becoming more critical problem considering the current effects of global warming and climate change in the region. The objectives of this study are to model spatial variation of aeolian sediment transport and to map Sediment Transport Rate (STR) by geostatistics in a fallow plot in the Central Anatolia. STRs for four consecutive wind cases with different vegetation cover rates were determined using the cyclone BEST sediment traps. Plant cover ratio and height changed between 8 and 25% and 3–12?cm throughout the research period, respectively, and soil moistures ranged between 10.9 and 12.7%. The windstorms lasted for 400, 835, 1240, and 50 minutes with the mean wind velocities of 8.6, 7.7, 7.7, and 6.3?m?s^?1, respectively, for cases 1, 2, 3, and 4. The calculated STRs varied between 0.0248?±?0.0170?kg?m^?1?h^?1 and 0.190?±?0.084?kg?m^?1?h^?1. Spatial analysis revealed that the spatial correlations were between 19 and 48?m and different spatial patterns occurred from one case to another. The study results indicated that the amount of transported sediment and its spatial variation were mostly related to velocity and duration of erosive wind in the fallow area of the arid region.     

Degradation and persistence of gamma-HCH and chlorpyrifos-methyl in Ponderosa pine bark

Residues of gamma-HCH and chlorpyrifos-methyl in Ponderosa pine bark (Pinus ponderosa Laws.) were determined 7-300 days after spray treatment, by a rapid extraction method using ethyl acetate and sodium sulphate, and analysis by gasliquid chromatography using either an electron-capture or nitrogen-phosphorus detector. The residue data were fitted into a power curve equation, Y = ax^b, to determine the rates of insecticide disappearance. The half-life values (μg cm^?2), as interpolated from the power curve, indicate that 50% disappearance occurred in 43 (± 9) days for gamma-HCH and 102 (± 26) days for chlorpyrifos-methyl. When half-life values, however, are computed from extrapolated initial deposits, 50% disappearance occurred in 6 (± 1) days for gamma-HCH and 15 (±4) days for chlorpyrifos-methyl.