Journal of Plant Diseases and Protection 

About: Journal of Plant Diseases and Protection is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Biology & Botany. It has an ISSN identifier of 1861-3829. Over the lifetime, 1183 publications have been published receiving 10696 citations.

Benefits of hyperspectral imaging for plant disease detection and plant protection: a technical perspective

Abstract: The detection and identification of plant diseases is crucial for an appropriate and targeted application of plant protection measures in crop production. Recently, intensive research has been conducted to develop innovative and technology-based optical methods for plant disease detection. In contrast to common visual rating and detection methods, optical sensors are able to measure pathogen-induced changes in the plant physiology non-invasively and objectively. Several studies showed that especially hyperspectral sensors are valuable tools for disease detection, identification and quantification on different scales from the tissue to the canopy level. This review describes the basic principles of hyperspectral measurements and different types of available hyperspectral sensors. Possible applications of hyperspectral sensors on different scales for disease detection and plant protection are discussed and evaluated. The advantages and disadvantages on each particular scale, as well as the impact of external factors, such as: light, wind, viewing angle, for measurements in laboratories, greenhouses and fields, are critically assessed in order to support researchers and agriculture technicians. Additionally, a comprehensive literature review about the use of hyperspectral sensors on these different scales for plant disease detection reflects the possibilities of non-invasive measurement systems. This highlights advantages of hyperspectral sensors when investigating plant–pathogen interactions through multiple examples. By some approaches, detection before visible symptoms appear is feasible. The potential of hyperspectral sensors as a tool for disease identification and quantification, based on disease characteristic changes in the plants spectral signature, is discussed as well. The review is concluded with an overview on different data analysis methods, which are required to extract key information from gathered hyperspectral datasets.

Quantitative analysis of the seasonal and tissue-specific expression of Cry1Ab in transgenic maize Mon810

Abstract: The tissue-specific expression and seasonal abundance of Cry1Ab protein were determined in transgenic maize plants (Mon810, variety ‘Novelis’) from two field trials located near Bonn and Halle, Germany. A total of 1085 samples were analysed by using Double Antiserum-Enzyme Linked Immun-osorbent Assay (DAS-ELISA). The Cry1Ab contents of various plant tissues (root, stem, upper leaf, lower leaf, anther, pollen and kernel) were determined at four different growth stages (BBCH19, BBCH30, BBCH61 and BBCH83) collected in 2001, 2002 and 2003. Mon810 showed the highest Cry1Ab contents in the leaves (5.5–6.4 µg g–1 fresh weight [fw]) at BBCH83, whereas the lowest Cry1Ab contents were detected in the pollen (1–97 ng g–1 fw). Cry1Ab content of residual root stocks collected in the field nine months after harvest was 15–17 n g g–1 fw. This demonstrated that the Cry1Ab concentration in residual root stocks was reduced to about one-hundredth of the fresh roots. The monitoring of Cry1Ab expression showed that the Cry1Ab contents varied strongly between different plant individuals.

Response of Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae) to extracts of cashew kernels

Abstract: Cashew kernels were extracted with six different solvents namely methanol, ethanol, water, acetone, pet-ether and n-hexane. The different extraction products were evaluated on C. maculatus adults for their mortality, ovicidal and adult emergence effects. The long-term protectant ability of the cashew kernel extracts and water absorption capacity of the treated cowpea seeds were also investigated. The results obtained showed that the steam distillate was most toxic to C. maculatus. The least toxic extracts on the insect were those of methanol and ethanol. The extracts drastically reduced oviposition in C. maculatus. The cowpea seeds treated with steam distillate had the lowest water absorption capacity, while the highest water absorption capacity was obtained in grains treated with ethanol and methanol. At 2.0% v/w cashew kernel extracts, the percentage water absorption capacity of cowpea seeds increased with increase in the interval of submergence. Steam distillate and the extracts of n-hexane, pet-ether and acetone completely prevented infestation and damage of the treated cowpea seeds for a period of three months as there was neither weight loss nor damage in the treated grains. In the grains treated with the methanol and ethanol extracts, damage of 20.17% and 9.76% were recorded, respectively. The results obtained from this study revealed that extract of cashew kernel is effective in controlling cowpea storage bruchid, C. maculatus and could serve as an alternative to synthetic insecticides for the protection of stored cowpeas against bruchids.

Quantifying the effects of previous crop, tillage, cultivar and triazole fungicides on the deoxynivalenol content of wheat grain — a review

Abstract: Deoxynivalenol (DON) is a mycotoxin produced by fungi of the genus Fusarium. Maximum tolerable DON concentrations for grain and selected wheat products were laid down by national and European legislative institutions to protect consumers from health risks associated with the intake of this mycotoxin. Among the factors that can be controlled by growers, previous crop, tillage, wheat cultivar and fungicide regimes were identified as the most important variables for DON contamination of wheat. Beyond the identification of the risk factors, their quantitative impact needs to be known for integrated control strategies. The purpose of this review was to extract information on the magnitude of DON reductions caused by agronomic methods or fungicide applications from recent publications. Efficacies of fungicides containing triazoles as active ingredient differed significantly (P= 0.004) in the studies published recently. This effect was solely based on a poor performance of fenbuconazole. No significant differences between triazole fungicide efficacies were observed after excluding fenbuconazole from the analysis. On average, triazole fungicides applied around the time of wheat anthesis reduced the DON content to 53 ± 4% of the grain obtained from untreated control plots. Planting wheat after crops other than maize reduced the DON content to 33 ± 11% compared to maize as the pre-crop. Using a mouldboard plough lowered the DON content to 33 ± 7% compared to minimal or no tillage plots. Cultivating commercially available moderately susceptible cultivars decreased the DON content down to 24 ± 7% compared to susceptible cultivars. Hence, careful choice of cultivar is currently the most effective agronomic method to decrease DON contamination levels in wheat followed by ploughing, avoiding maize as pre-crop and applying triazole fungicides at wheat anthesis. If DON contents of reference scenarios (for instance long term average DON contamination levels for particular cultural practices and regions) are known, the factors extracted in this review may be useful to estimate how many risk factors need to be avoided to decrease DON contents below the limits given in the actual legal regulations.

Effects of sulfated polysaccharide and alcoholic extracts from green seaweed Ulva fasciata on anthracnose severity and growth of common bean (Phaseolus vulgaris L.)

Abstract: Seaweed compounds can play important roles in either plant growth promoting or plant-pathogen interactions. The aim of this study was to evaluate the potential of crude extracts and sulfated polysaccharides isolated from the green macroalga Ulva fasciata in the control of bean anthracnose caused by Colletotrichum lindemuthianum as well the influence in the plant growth. Sulfated polysaccharides, called ulvan, were extracted with hot water, precipitated in ethanol and identified by chemical and spectroscopic methods (13C NMR). The contents of sulfate, uronic acid, protein and monosaccharides were determined. In order to obtain the crude extracts, the dried alga was extracted with methanol in Soxhlet apparatus or with ethanol at room temperature. The effect of ulvan (0.1; 1; and 10 mg ml−1) and crude extracts were tested in vitro on conidial germination and mycelial growth of C. lindemuthianum and also on the seed germination and seedling length of bean. Under greenhouse conditions, bean plants (Phaseolus vulgaris L.) were sprayed twice with ulvan or extracts and inoculated two days after the second application. The anthracnose severity was evaluated 7 days and aerial plant dry weight 14 days after inoculation. The soluble methanolic extract inhibited the mycelial growth of C. lindemuthianum in vitro, but did not reduce the disease severity under greenhouse conditions. Foliar spray of methanolic extracts enhanced the dry weight of bean plants by 20%. In contrast, ulvan increased in vitro the mycelium growth and the conidia germination of the fungus, but in greenhouse, the spray of 10 mg ml−1 ulvan reduced the anthracnose severity by 38% without affecting plant growth. The results indicate that ulvan is probably able to induce resistance to bean anthracnose.