Dušanka Inđić

Phytotoxicity of chlorpyrifos to white mustard (Sinapis alba L.) and maize (Zea mays L.): potential indicators of insecticide presence in water.

Chlorpyrifos is a hazardous insecticide and important pollutant of the environment. The EU Directive 2008/105/EC lists it as one of the priority water pollutants. Its presence is mainly detected by chemical methods but, since biological tests have gained in importance in the last few years, this study aimed to assess the potentials of white mustard (Sinapis alba L.) and maize (Zea mays L.) as indicators of water pollution. The phytotoxic effects of chlorpyrifos (rates 0.05-10μg a.i./l) were assessed based on physiological (germination energy and germination) and morphological traits (root and shoot length, fresh and dry weights) of the tested species. A slightly modified filter paper method was used and the results were processed by Duncan`s multiple range test and Probit analysis (EC50). According to the Directive, the maximal allowable concentration (MAC) of chlorpyrifos in water is 0.1μg a.i./l. When applied at the MAC value, chlorpyrifos inhibited germination energy and germination (11.25%) of white mustard, as compared to the control (91.5; 93.5%), and its hypocotyls and epicotyls failed to form. At the rates 50% below the MAC, germination energy and germination (87.75; 88.25%) were significanty inhibited, as well as root and shoot growth of seedlings. Chlorpyrofos did not affect the germination energy and germination of maize, while all morphological traits were significantly reduced by chlorpyrifos at the MAC rate. The EC50 of chlorpyrifos was 0.09μg a.i./l for germination of white mustard and 3.21μg a.i./l for maize. Projekat Ministarstva nauke Republike Srbije, br. III 43005:: Improvement of remediation technologies and development of methods for risk assessment of contaminated sites

Phytotoxic effects of fungicides, insecticides and nonpesticidal components on pepper depending on water quality

Modern agriculture relies on simultaneous application of fungicides, insecticides, fertilizers and adjuvants. The selection of compounds for tank-mixes has been rarely studied and it presents a risk in the application of pesticides but the quality of water should also be considered. The aim of this study was to assess the phytotoxic effects of several fungicides, insecticides, a complex fertilizer, an adjuvant and their mixtures on pepper (Capsicum annuum L.) as a test plant, depending on water quality. The effects of the pesticides: azoxystrobin (Quadris, 0.75 l/ha), mancozeb (Dithane M-70, 2.5 kg/ha), thiamethoxam (Actara 25-WG, 0.07 kg/ha) and cypermethrin (Cipkord EC-20, 0.3 l/ha), a complex fertilizer (Mortonijc plus /hereinafter: M+/ 3kg/ha), an adjuvant (Sillwet 77-L, 0.1 l/ha) and their mixtures, were assessed depending on the quality of water (well water - slightly alkaline, very hard and with high nitrite content; tap water - neutral and slightly hard; surface water - alkaline, slightly hard and with high content of nitrite and ammonia) using a puncture method. The effects were assessed after seven days by measuring the diameter of chlorosis and/or necrosis around puncture sites, and were expressed in mm2. The significance of differences between treatments was analyzed using a one-way ANOVA (LSD 0.05 %). In the slightly alkaline and very hard well water, all spray liquids containing Dithane M-70 caused a significant increase in leaf chlorosis area (from 6.0 to 25.2 mm2), compared to the control and other treatments. In the neutral and slightly hard tap water, all spray liquids containing Dithane M-70 caused a significant increase in leaf chlorosis (5.3 to 7.9 mm2) compared to the control and the other spray liquids, although its phytotoxicity in that water was at a lower level than it was in well water. However, in the weakly alkaline and slightly hard surface water from the river Sava, Dithane M-70, Dithane M-70 + Actara WG-25, Dithane M-70 + Sillwet L-77, and Dithane M-70 + Actara 25-WG + M+ showed a significant increase in phytotoxicity, compared to the control. [Projekat Ministarstva nauke Republike Srbije, br. III46008]

Screening test for detection of Leptinotarsa decemlineata (Say) sensitivity to insecticides.

SUMMARy In 2009, the sensitivity of 15 field populations of Colorado potato beetle (Leptinotarsa decemlineata Say.) - CPB was assessed to chlorpyrifos, cypermethrin, thiamethoxam and fipronil, four insecticides which are mostly used for its control in Serbia. Screening test that allows rapid assessment of sensitivity of overwintered adults to insecticides was performed. Insecticides were applied at label rates, and two, five and 10 fold higher rates by soaking method (5 sec). Mortality was assessed after 72h. From 15 monitored populations of CPB, two were sensitive to label rate of chlorpyrifos, one was slightly resistant, 11 were resistant and one population was highly resistant. Concerning cypermethrin, two populations were sensitive, two slightly resistant, five were resistant and six highly resistant. Highly sensitive to thiamethoxam label rate were 12 populations, while three were sensitive. In the case of fipronil applied at label rate, two populations were highly sensitive, six sensitive, one slightly resistant and six were resistant. The application of insecticides at higher rates (2, 5 and 10 fold), that is justified only in bioassays, provided a rapid insight into sensitivity of field populations of CPB to insecticides.

Integrated management of causal agents of postharvest fruit rot of apple.

One of the major causes of poor quality and fruit loss (during storage and transport) are diseases caused by phytopathogenic fungi. Economic losses which are the consequence of the phytopathogenic fungus activity after harvest exceed the losses in the field. The most important postharvest fungal pathogens of apple fruits are: Botrytis cinerea Pers. ex Fr., Penicillium expansum (Lk.) Thom., Cryptosporiopsis curvispora (Peck.) Grem., Colletotrichum gloeosporioides (Penz.) Sacc., Monilinia sp., Gloeosporium album Osterw, Alternaria alternata (Fr.) Keissler, Cladosporium herbarium Link., Cylindrocarpon mali (Alles.) Wollenw., Stemphylium botryosum Wallr. The use of available protection technologies can significantly reduce losses caused by pathogens in storage. The concept of integrated pest management (IPM) in apple fruits i.e. sustainable approach in control of causal agents of postharvest fruit rot, using cultural, physical, biological and chemical measures, to minimize economic, health and risks to consumers and environment, is presented in the paper.

Maize defence mechanisms against the European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae)

ABSTRACT Maize is arguably the most widely grown crop in the world, but it is often associated with one of its major insect pests, the European corn borer (ECB). The damage caused by this species to maize production is generally variable, but in many cases it is economically significant. This review paper provides an overview of the research findings on the natural plant defence mechanisms against ECB larvae published till now. What is resistance and how it is achieved, what is the chemical response of maize plants to insect feeding and how tolerance can be increased. A short introduction in breeding for resistance and a discussion if the mentioned traits can be used in conventional breeding in order to create maize hybrids less affected by ECB are given.

Antifeeding Activity of Several Plant Extracts Against Lymantria dispar L. (Lepidoptera: Lymantriidae) Larvae

SUMMARY Lymantria dispar L. is the most devastating polyphagous pest of deciduous forests, orchards and urban greenery. To prevent damages that L. dispar larvae cause in forestry, agriculture and horticulture, mechanical measures and the use of biological insecticides are the most frequently applied practices. However, the use of conventional insecticides is inevitable in crop protection and forest management on smaller areas, especially in gradation years. However, inadequate use of these chemicals has led to disturbance of biocoenotic balance, outbreaks of some previously less harmful organisms and pesticide residues in soil and watercourses in some regions. To mitigate these consequences it is necessary to harmonize L. dispar control with integrated management principles by applying selective and less toxic insecticides. Therefore, the potential of botanical insecticides and antifeeding substances is gaining in importance. The aim of this study was to assess the influence of ethanol extracts (1, 2 and 5%) of Ambrosia artemisiifolia L., Erigeron canadensis L., Daucus carota L., Morus alba L. and Aesculus hippocastanum L. on the feeding intensity of L. dispar larvae, i.e. to evaluate their antifeeding activity under the conditions of “no-choice” test. Ten larvae per repetition were placed in Petri dishes and offered oak leaf slices (2 x 9 cm 2 /repetition) previously dipped in plant extract or ethanol (1, 2, and 5%) for the control. Feeding intensity, expressed as a percentage of consumed leaf area (%), was measured after 48 h. For assessing the antifeeding activity of plant extracts AFI was calculated and the extracts were classified according to scale: no antifeeding activity, slight antifeeding activity, moderate antifeeding activity and strong antifeeding activity. Data were ana