Inhibition of oomycetes by the mixture of maleic acid and copper sulfate

After the discovery of the protective activity of Bordeaux mixture against plant disease caused by oomycetes, copper compounds have been used for over a century as a significant plant protection strategy. However, application of excessive copper can cause adverse effects through long-term heavy metal accumulation in soils. Therefore, it is necessary to develop new strategies to reduce or replace copper in pesticides based on organic and low-input farming systems. Organic acids are eco-friendly in nature. In this study, we tested the antifungal and anti-oomycete activity of maleic acid (MA) and copper sulfate (CS) against thirteen plant pathogens. Treatment of MA and CS mixture showed strong anti-oomycetes activity against Phytophthora cambivora, P. capsici and P. cinamomi. Moreover, the concentration of CS in the activated mixture of MA and CS was lower than that in the activated CS only, and the mixture showed synergy or partial synergy effects on the anti-oomycete activity. Application of a wettable powder formulation of MA and CS mixture (MCS 30WP; 26.67 % MA and 3.33 % CS) exhibited excellent protective activities in pot experiments with control values of 73 % Phytophthora blight on red pepper, 91 % damping-off on cucumber, and 84 % Pythium blight on creeping bentgrass, which are similar to those of the CS wettable powder formulation (6.67 % CS) containing two times the CS content in MCS 30WP. These observations suggest that the synergistic effect of the MA and CS combination is a sustainable alternative for effective management the destructive oomycete diseases.

Lethal and Sublethal Toxicity of Pesticides Used in Fruit Growing on the Parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae): Implications for Integrated Fruit Fly Management

The larval-pupal endoparasitoid Diachasmimorpha longicaudata (Ashmead, 1905) is considered one of the main biological control agents of fruit flies Ceratitis capitata Wiedemann (1824) and Anastrepha fraterculus Wiedemann (1830) in Central and South America. The application of pesticides for disease and insect-pest management in fruit species may have adverse effects on the parasitoid. The objective of this study was to evaluate the lethal and sublethal effects via residual contact of commercial pesticide formulations on D. longicaudata. The active ingredients thiamethoxam, indoxacarb, chlorpyrifos, deltamethrin, spinetoram, spinosad, phosmet, lambda-cyhalothrin, malathion, dimethoate, and methidationa showed high toxicity to adults (100% mortality) after 96 h and were classified as harmful (Class 4). In contrast, the formulations of azadirachtin (Agroneem 850 EC, Azact 2.4 EC, Azamax 12 EC, and Fitoneem 850 EC), chlorantraniliprole, bordeaux mixture, sulfur, lufenuron, lime sulphur, novalurom, and mancozeb were rated as innocuous (<10% mortality). In addition, the formulations azadirachtin did not reduce the parasitism and the emergence rate of the F0 generation, the same pesticides added to chlorantraniliprole, azadirachtin A+B (Agroneem 850 EC), and lufenuron did not cause reduction in parasitism and emergence rate of the F1 generation of D. longicaudata. The use of pyrethroids, organophosphates, spinosyns, oxadiazines, and neonicotinoids should be used with caution in IPM programs. While pesticides chlorantraniliprole, azadirachtin formulations, bordeaux mixture, lufenuron, lime sulphur, and mancozeb do not cause lethal and sublethal effects for D. longicaudata adults. The results of this study provide important information for use in integrated pest management programs for fruit fly management.

GREENER METHODS OF CONTROL FOR MICROBIAL DISEASES OF POMEGRANATE USING COPPER OXIDE NANOPARTICLES AND BETEL LEAF EXTRACT

Pomegranate (Punica granatum) is an important exportable fruit crop of India that faces major losses when infected by fungal wilt and bacterial blight. The present investigation is aimed to isolate and identify the causative organism of the plant disease infecting the stem of pomegranate. The identification based on microscopic, morphological characterization and 18SrRNA sequencing confirms as Mariannaea elegans. The crude extracts of various leaves of plants viz Psidium guajava, Picrorhiza kurroa and Piper betel were used to evaluate antifungal activity using agar well diffusion method. Results confirm that ethanolic extract of Piper betel extract (0.5mg/ml) show zone of inhibition against Mariannea elegans. The research demonstrates that commonly used fungicides viz., Manocozeb/ Matalxy and Carbendazim showed very little inhibition as compared to the Piper betel ethanolic extracts and hence the latter proves to be a better and eco-friendlier control alternative. The present study was also aimed at finding remedies for bacterial blight. The blight pathogen was isolated from the fruit pericarp and identified using morphological and biochemical characters to be Xanthomonas axonopodis pv. punicae (Xap). Nanoparticles synthesized using green method, Copper oxide nanoparticles (1mg/ml) synthesized using Azadirachta indica leaf extract showed excellent inhibitory effect against the blight pathogen as compared to Bordeaux mixture, commonly used as an antimicrobial spray by farmers.

Copper-induced Haemolytic Anaemia

Acute copper toxicity is uncommon in Western countries and is often the result of accidental consumption or a suicide attempt. We report the case of a 65-year-old man presenting to the accident and emergency department after a suicide attempt with ingestion of Bordeaux mixture, ibuprofen, acetaminophen and bleach. Primary evaluation showed caustic oesophagitis, toxic hepatitis and acute renal injury, which were treated with supportive care. During admission, he developed a non-immune haemolytic anaemia associated with high levels of copper in urine and blood. Chelation treatment with penicillamine was started and evolution was favourable after 1 month of treatment. Copper poisoning can be lethal. Prompt diagnosis and treatment are key for a favourable prognosis.

Management of Anthracnose Disease of Aloe vera in Bangladesh

Aims: To identify the causal organisms of anthracnose disease of Aloe vera in Bangladesh and to manage this disease in field condition. Study Design: The experiment was designed by Randomized Complete Block Design (RCBD) with three replications. Place and Duration of Study: The field experiments were conducted in Natore, Bangladesh and the laboratory experiments were carried out at the Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh from January, 2017 to December, 2018. Methodology: The causal organism Colletotrichum gloeosporioides was isolated by tissue plating method and identified based on morphological and cultural characteristics and that was confirmed by pathogenicity test. Infested farmer’s fields were selected in rainy season under natural epiphytic condition to evaluate the efficacy of eleven treatments. Results: Among the treatments, Bordeaux mixture gave best result against this disease. Moreover, Tilt 250 EC and Folicur 25 EC and Garlic bulb extract showed better effect against the disease than the other treatments. Lime also has moderate effect against anthracnose disease of A. vera. In 2017, after 4th spray, the lowest incidence was recorded in Bordeaux mixture (58.33%) which was statistically identical with Folicur (64.58%), Tilt (64.58%) and Garlic bulb extract (66.67%). Similarly, the lowest disease severity was found in Bordeaux mixture (3.55) followed by Folicur (5.67%), Tilt (6.67%) and Garlic bulb extract (7.67%). Similar result also found in 2018. After 4th spray, the lowest incidence was recorded in Bordeaux mixture (38.58%) which was statistically identical with Lime (41.66%) and Garlic bulb extract (45.83%). Similarly, the lowest disease severity was found in Bordeaux mixture (0.20%) followed by Lime (0.25%) and Garlic bulb extract (0.36%). Conclusion: Garlic bulb extract could be used as eco-friendly approach. Moreover, use of Bordeaux mixture is better than the traditional use of lime. From chemical pesticides, Tilt 250 EC and Folicur 25 EC could be used for controlling the disease as the last option.

Control of mildew in vines with cinnamon extract and catalase activity in organic production

Management with synthetic fungicides in the control of phytopathogens in viticulture can cause environmental pollution and contamination with residues in grape cluster. The objective of this study was to verify the effect of aqueous cinnamon extract on the in vitro and in vivo control of Plasmopara viticola on catalase activity on ‘Isabel Precoce’ vines. The treatments used were: aqueous cinnamon extract (ACE) at concentrations of 0.12; 0.25 and 0.50% plus 0.25% vegetable oil (VO); being the standard treatments VO (0.25%), Bordeaux mixture 1:1:100 (lime: copper sulfate: water) and water only. The germination tests of P. viticola sporangia were carried out in incubation periods of 4 and 24 hours of the pathogen in contact with the treatments. In addition, the area under the disease progress curve (AUDPC) and the activity of the catalase enzyme were estimated in plants grown in the greenhouse. The results indicated that the treatments with 0.12%, 0.25% and 0.5% ACE with VO reduced the germination of P. viticola. In relation to the AUDPC, the 0.25% dose of VO associated ACE reduced 65% and 67% in leaf discs and vines in the greenhouse, respectively. This fact is related to the induction of CAT activity provided by this dose in the periods of 2HBA, 2HAI and 4HAI. Thus, it can be said that the ACE associated with VO can be used to control the downy mildew of the ‘Isabel Precoce’ vine.

Pesticide exposure and rhinitis: A cross-sectional study among farmers in Pitsanulok, Thailand

Background: Pesticide exposure has been suspected to cause rhinitis, a common disease that affects the health and wellbeing of millions of people around the world. The objective of this cross-sectional study was to examine the association between pesticide use and rhinitis prevalence among farmers in Phitsanulok province, Thailand. Methods: Data on pesticide use and rhinitis use were collected by an in-person interview questionnaire. Data from 9,649 participants were included in the analysis. The association between pesticide exposure and rhinitis was determined by multiple variable logistic regression, adjusted for potential confounding factors. Results: It was found that 6.3% of study participants had rhinitis, which was defined as having one or more of the following symptoms: sneezing, runny nose, and nasal congestion, within the past year. The study found each type of pesticide (insecticides, herbicides, fungicides, rodenticides, molluscicides) to be significantly associated with rhinitis, with the odds ratio ranging from 1.67 (95% CI 1.41-1.99) for the fungicide group to 7.19 (95% CI 4.67-11.06) for insecticide. For individual pesticides, the study found 33 out of 35 to be significantly associated with rhinitis with the OR values ranging from 1.30 (95% CI 1.00-1.69) for alachlor to 5.67 (95% CI 3.16-10.16) for Bordeaux mixture. Conclusions: This study found a prevalence of rhinitis among farmers in Phitsanulok, Thailand to be associated with the long-term exposure of many individual pesticides. This finding was consistent with other literature. Effects of pesticide on rhinitis should receive more attention from the public health and other organizations responsible for the farmers’ health.

Common diseases of snap bean (phaseolus vulgaris l.) for biological production

The main diseases of snap bean (Phaseolus vulgaris L.) for organic production and the possibilities for control have been studied. The strategic directions of the experimental work included: monitoring of diseases; study of pathogens’ variability; the field resistance of the Bulgarian bean varieties “Evros” and “Tangra” to the diseases in organic farming; optimization of the phytosanitary state of the crop through the authorized plant protection products. It has been established that seed-borne diseases are of predominant importance for organically grown garden beans. These are bacterial blight Xantomonas axanopodis pv. phaseoli, halo blight Pseudomonas syringae pv. phaseolicola and anthracnose Colletotrichum lindemuthianum. The screening of Bulgarian bean varieties for disease resistance showed that the “Evros” variety is relatively resistant to bacterial blight and anthracnose, which makes it suitable for growing by biological technologies. The development of bacterial blight and anthracnose after five treatments with the fungicide Bordeaux Mix 20VP (Bordeaux mixture 200 g/kg Cu +) with an interval of 10-14 days, starting from the flowering phase, is in the range up to 12.5%.