In the years 2000–2003 under Polish climatic conditions early blight occurred at different level of incidence on over 90.6% of surveyed fields. Time of disease appearance in different regions was closely related to climatic conditions. On average, early blight appeared on potato plants 59.3 days after planting, earlier than late blight. In the years 2001–2003, efficacy of six selected fungicides in early blight control was examined in field conditions. Experiments carried out in the Department of Potato Protection and Seed Science of Plant Breedingand Acclimatization Institute. Field trials located in two sites – at Bonin and Stare Olesno revealed much slower development of early blight on these fields where chemical protection was applied as compared to untreated control. Efficacy of plant protection program carried out in Bonin over three years varied from 40% to 63.9%. Effectiveness of selected products was higher in Stare Olesno at higher infection pressure, and ranged from 49.8% to 66.6%. However, efficiency of chemical protection in early blight suppressing is not as satisfactory as in late blight control. In field experiments good control of early blight resulted in tuber yield increase. In Bonin yield increase varied from 5.5 to 24.2% and in Stare Olesno from 12.2 to 34.4%.
The aim of the study carried out during 2002–2004 was to assess the effects and economic effectiveness of application of fungicides and insecticides in winter triticale crops. Its leaves were attacked by pathogenic fungi in 43.2% to 52.2% and the damage to leaf blade surfaces by cereal leaf beetle (Oulema spp.) ranged from 23.6% to 34.4%. The effectiveness of applied fungicides ranged from 44.7% to 90.8%, and that of insecticides was within 70.1% and 94.4%. The saved crops were evaluated for PLN 198 to 1 171 per ha. The cost coverage ratio ranged from 0.7 to 9.9 and the treatment profitability index ranged from 0.9 to 7.4. Cost index in percentage ranged from 0.8 to 8.5, with its average value of 4.2.
Digitaria insularis (sourgrass) is a monocotyledon weed of difficult control and high invasive behavior. Atrazine is widely applied in the Americas to control weeds in maize culture, but its efficiency against D. insularis is limited. The incorporation of atrazine into poly(epsilon-caprolactone) nanocapsules increased the herbicidal activity against susceptible weeds; however, the potential of this nanoformulation to control atrazine-tolerant weeds including D. insularis has not yet been tested. Here, we evaluated the post-emergent herbicidal activity of nanoatrazine against D. insularis plants during initial developmental stages. The study was carried out in a greenhouse, using pots filled with clay soil. Plants with two or four expanded leaves were treated with conventional or nanoencapsulated atrazine at 50 or 100% of the recommended dosage (1,000 or 2,000 g ∙ ha−1), followed by the evaluation of physiological, growth, and control parameters of the plants. Compared with conventional herbicide, both dosages of nanoatrazine induced greater and faster inhibition of D. insularis photosystem II activity at both developmental stages. Atrazine nanoencapsulation also improved the control of D. insularis plants, especially in the stage with two expanded leaves. In addition, nanoatrazine led to higher decreases of dry weight of fourleaved plants than atrazine. The use of the half-dosage of nanoatrazine was equally or more efficient in affecting most of the evaluated parameters than the conventional formulation at full dosage. Overall, these results suggest that the nanoencapsulation of atrazine potentiated its post-emergent herbicidal activity against D. insularis plants at initial developmental stages, favoring the control of this atrazine-tolerant weed.
The results of experiments showed an effect of magnetized water on the effectiveness of some selected zoocides. The control of red spider mite (Tetranychus urticae Koch) by Ortus 05 SC showed the highest effectiveness with strongly magnetized water, with use of one magnetizer and two semi-rings. On the other hand, the application of Magus 200 SC in combination with magnetized water showed a decreased effectiveness of insecticide. In the control of grain weevil (Sitophilus granarius L.), an increase in the effectiveness was found for the zoocides Talstar 100 EC, Karate 025 EC and Winylofos 550 EC in combinations with strongly magnetized water (three magnetizers or one magnetizer with two rings). In case of Sumi-Alpha 050 EC, high effectiveness of the treatment was obtained in combinations where water was magnetized in lesser degree, with use of one or two magnetizers. No significant differences were found in the effect of magnetized water on germination of bean (Phaseolus vulgaris L.) and cuckoo flower (Cardamine amara L.) plants.
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