Characterization of α-amylase and its activity from mustard aphid Lipaphis erysimi (Kalt.) (Hemiptera) and its inhibition by Rorippa indica defensin

Abstract

Lipaphis erysimi Kaltenbach is one of the economically important pests of Indian mustard Brassica juncea. Plant defense against these pests include impairing digestive processes in the insect gut. Thus, for an effective pest management, it is imperative to understand the digestive enzymes present in the pest. The present study involves the characterization of mustard aphid α-amylase and the efficacy of a potent insecticidal agent, RiD (Rorippa indica defensin) against it. The total protein of L. erysimi was analysed to determine the α-amylase activity present in it. The relative α-amylase activity in the total protein was assayed by the dinitrosalicylic acid (DNS) procedure, using 1% soluble starch as substrate and was observed to be 2.32?±?0.025?U/mL of the total protein. The optimum temperature for α-amylase activity was found to be 35?°C and optimum pH was recorded as 6.5. Presence of RiD showed a decrease in the α-amylase activity in a non-competitive way. Moreover, cryo-sections of the aphid midgut also revealed bound RiD in the confocal analysis.     

Pest management in fodder cowpea (Vigna unguiculata L. Walp.) through mixed‐and inter‐cropping in India

Abstract

In a study of the effects of inter‐cropping and mixed‐cropping of cowpea and sorghum during the kharif, 1982 and 1983, the incidence of leafhoppers and the damage caused by defoliators were most reduced in a row inter‐crop, less in mixed, within row, farming and least in a pure crop of cowpea. Greater green fodder and dry‐matter yields of cowpea were obtained in inter‐crop between rows and in mixed‐crop, within row farming.     

Important invasive species and its pest status in Turkey: Halyomorpha halys (Stål) (Heteroptera: Pentatomidae)

Journal of Plant Diseases and Protection - The brown marmorated stink bug, Halyomorpha halys (Stål), is a pest of many annual and perennial agricultural products. The species is native to...     

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.     

Morphological and molecular identification of Fusarium oxysporum f. sp. narcissi on poet’s daffodil (Narcissus poeticus L.) in Serbia

Journal of Plant Diseases and Protection - In autumn 2018, daffodil (narcissus) plants with basal bulb rot were noticed in a plantation in locality Jasika, Serbia. Morphological characterization...     

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.     

Two-year Investigations on Herbicide-Resistant Silky Bent Grass (Apera spica-venti L. Beauv.) Populations in Winter Wheat��Population Dynamics, Yield Losses, Control Efficacy and Introgression into Sensitive Population

In this study, the results of two-year investigations on herbicide resistance in silky bent grass (Apera spica-venti) populations are presented. Two populations of A. spica-venti were sown in a winter wheat field at the Ihinger Hof Research Station near Stuttgart in Germany in October 2008. Whole-plant bioassays conducted with both populations in the greenhouse before the field trial was set up revealed that population A was strongly resistant to acetolactate synthase (ALS)-inhibitors, whereas population B was sensitive to this group of herbicides. Each block was treated with isoproturon, fenoxaprop-P-ethyl, sulfosulfuron and meso-iodosulfuron at the recommended field dose. One treatment remained unsprayed. It was found that the average number of silky bent grass panicles was significantly higher in the second year (2010) with 343 panicles m^{? 2} in the untreated control compared to 44 panicles m^{? 2} in the first year (2009). Efficacy of both ALS-inhibitors was significantly reduced in the resistant population compared to the sensitive population. Grass-weed plants surviving treatments with ALS-inhibitors produced the same number of seeds as the untreated plants. It was found that germination rate of seeds from the resistant population was more than threefold higher than from the sensitive population. Grain yield was equal in all treatments and populations in 2009. In 2010, applications of isoproturon and fenoxaprop-P-ethyl resulted in higher grain yields, with a mean of 4.6 t ha^{? 1} compared to an average of 3.9 t ha^{? 1} in the plots treated with sulfosulfuron and meso-iodosulfuron and 4.3 t ha^{? 1} in the untreated plots. However, these differences were not statistically significant. The sensitive population of the second generation (2009/2010) was approximately 20% more tolerant to ALS-inhibitors than the sensitive population of the first generation (2008/2009) which indicates introgression of herbicide resistance traits already after one year. These results clearly show that herbicide resistance to ALS-inhibitors in silky bent grass is likely to spread rapidly causing significant economic losses. Therefore, management strategies need to be developed and tested to prevent and overcome herbicide resistance in European cereal production systems.     

Response to the letter on “Climatic distribution of citrus black spot caused by <Emphasis Type="Italic">Phyllosticta citricarpa.</Emphasis> A historical analysis of disease spread in South Africa” by Fourie et al. (2017)

In a previous study, Martínez-Minaya et al. (European Journal of Plant Pathology 143, 69–83, 2015) performed an analysis of climate-based distribution of citrus black spot (CBS) in South Africa. It was found that CBS was initially confined to humid areas with summer rainfall, but later spread to arid steppe and even desert climates. A strong spatial autocorrelation of CBS distribution was found. Fourie et al. (European Journal of Plant Pathology, 2017) take a critical view of our study, but without presenting any analysis of results to refute our findings. Furthermore, Fourie et al. (European Journal of Plant Pathology, 2017) appear to have misunderstood our work, since many of their criticisms relate to the potential distribution of CBS in Europe, which is beyond the scope of our original study. Fourie et al. (European Journal of Plant Pathology, 2017) highlight the limitations of climate classifications in species distribution modelling. However, this was made explicit in our study, indicating that it was a preparatory work and further advanced modelling studies, including spatial effects, will be needed. Fourie et al. (European Journal of Plant Pathology, 2017) incorrectly assume that we used all of South Africa as the background in the spatial autocorrelation analysis. However, only citrus areas were used and a strong spatial autocorrelation was detected at all distances evaluated. Contrary to what Fourie et al. (European Journal of Plant Pathology, 2017) suggest, similar climate distributions of CBS were obtained at 5′ and 30′ resolution, and also with the national land-cover map of South Africa. The figure comparison presented by Fourie et al. (European Journal of Plant Pathology, 2017) appears to ignore the fact that the maps we used were grid cells of 10 × 10 km and not the line polygons they suggest. Therefore, we consider the conclusions from the Martínez-Minaya et al. (European Journal of Plant Pathology 143, 69–83, 2015) remain entirely valid.