Four products allowed in organic farming (kaolin, insecticidal soap, neem oil soap, spinosad) as alternatives to chemical insecticides, were evaluated for the control of Metopolophium dirhodum (Walker, 1849) (Hem.: Aphididae). In addition, number of the newborn nymph and host selection for the treated and untreated rose (Rosa hybrida L. cv. First Red) leaves were examined. The toxicities of used natural products were compared with the diazinon and control (water). Rose saplings were used as experimental material. The application was repeated twice in the same greenhouse. Evaluations in populations were done on 1, 3, 5, 7, 10 and 14 days after applications. Insecticidal soap showed toxicity between 50.45 % and 74.0 % until fifth day and its toxicity decreased in the following days. Neem oil soap was non-toxic (15.09%-19.71%) at first application but, in the second application, its toxicity was increased (36.96%-72.27%). Repeated kaolin application ended with a positive result of 66.87% control. Spinosad had no effect on aphid. It was observed that M. dirhodum population was decreased by repeated (twice) applications of kaolin, insecticidal soap and neem oil soap. However, they could not control the aphid populations completely. In choice tests, the numbers of living aphids and newborn nymphs on rose leaflets treated with kaolin, neem oil soap, and insecticide soap were lower than those not treated. These three products were found to be repellent for M. dirhodum.
The spread of Northern [Exserohilum turcicum (Pass.) K.J. Leonard & Suggs] and Southern [Bipolaris maydis (Y.Nisk. & C. Miyake) Shoemaker] leaf blight diseases in main corn (Zea mays L.) production areas in Turkey The spread of Northern [Exserohilum turcicum (Pass.) K.J. Leonard & Suggs] and Southern [Bipolaris maydis (Y.Nisk. & C. Miyake) Shoemaker] leaf blight diseases in corn was investigated in 5 geographical regions including 13 different provinces between the years of
Northern corn leaf blight caused by Exserohilum turcicum is one of the most significant diseases in maize‐growing fields, resulting in yield reduction worldwide. Genetic diversity and mating‐type of E. turcicum were determined using isolates collected from 7 important maize cultivation provinces in 4 different geographic regions of Turkey during 2014–2015. Multilocus haplotypes of E. turcicum isolates were characterized using 13 simple sequence repeats (SSR) primer pairs, which were amplified in PCR multiplex reactions. The evaluation of mating‐type ratio generated from the E. turcicum population was by χ2 significance test. MAT‐1 and MAT‐2 mating‐type were shown in the population; however, the χ2 significance test did not support the sexual reproduction hypothesis in any region. The E. turcicum population was found to produce predominantly asexual reproduction in Turkey. Numerous E. turcicum isolates showed very high genetic similarity and did not show a distinct cluster dependent on region or mating‐type on a dendrogram of genetic diversity. This result showed that one‐hundred per cent similarity in most of the collected isolates from different regions might also support long‐distance migration.
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