Tag Archives: pollen beetle

307-310 L. Narits
Occurrence of pests and stem rot on various oil crops
Abstract |

Occurrence of pests and stem rot on various oil crops

L. Narits

Jõgeva Plant Breeding Institute, Aamisepa 1, Jõgeva, 48309, Estonia;e-mail: Lea.Narits@jpbi.ee

Abstract:

The purpose of this study was to find an oil crop with no serious problems with pests and diseases, making it suitable for organic farms.The spring oilseed rape is the most important oil crop in Estonia. Winter turnip rape andwinter oilseed rape are alternatives to spring rape.In the present exploration the following were investigated: incidence of flea beetles,pollen beetles and cabbage seed weevils, and the number of blind stalks and infection of stem rot on spring oilseed rape, winter oilseed rape and winter turnip rape.In winter oilseed rape and winter turnip rape trials no pesticides and fungicides were usedduring the growing period, but there was a variant of seed treatment by ‘Rapcol’ (phurathiocarb + matalaxil + fludioxonil) in comparison with the non-treated variant. Spring oilseed rape trials were treated by ‘Rapcol’ before sowing and sprayed by ‘Fastac’ (alpha-cypermethrin) at the beginning of flowering (stage of development – 61).The following results were obtained: flea beetles appeared most on winter oilseed rape,least on winter turnip rape. Pollen beetles appeared most on spring oilseed rape, least on winter turnip rape. Most pods damaged by pollen beetles’ larvae were found on winter oilseed rape, least on winter turnip rape. Damage by cabbage seed weevil was minimal in all the oil crop trials. Stem rot infection was high on spring oilseed rape, least on winter turnip rape.By the results of exploration it can be concluded that winter turnip rape had the lowestinfection by pests and disease and therefore has good potential for sustainable agriculture.

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17–29 K. Hiiesaar, L. Metspalu, P. Lääniste, K. Jõgar, A. Kuusik and J. Jõudu
Insect pests on winter oilseed rape studied by different catching methods
Abstract |
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Insect pests on winter oilseed rape studied by different catching methods

K. Hiiesaar¹, L. Metspalu¹, P. Lääniste², K. Jõgar¹, A. Kuusik¹ and J. Jõudu²

¹Department of Plant Protection, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: hkelly@eau.ee
²Department of Field Crop Husbandry, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia

Abstract:

The distribution, species association and number of pest insects on winter oilseed rape of varieties ‘Wotan’ and ‘Express’ were studied in field experiments. Three catching methods were used: black plastic basins on the soil surface between plants, yellow flight traps filled with water at the height of the crop canopy and the shaking of plants above a plastic basin. The most abundant pest species was the pollen beetle,Meligethes aeneus, while the number of individuals from the species M. virescens in traps was much lesser. The other  important group of pest insects were weevils Ceutorrhynchus spp., the most common of which was the cabbage seed weevil, C. assimilis.  Three species of flea beetlesPhyllotreta undulata, Ph. vittata and Ph. nemorum were typical contents of traps during May. In the last decade  of May, there was a large number of thrips (Thysanoptera, Tripidae) in traps.
Winter oilseed rape began to flower to some extent later, when pest insects of cruciferous plants had ended their hibernation. Therefore, the pests first inhabited weeds and already flowering plants, from where they later moved onto winter oilseed rape.
    In the field of winter oil seed rape, chemical pest control with a pyrethroid, Fastac, did not significantly influence the abundance of  pest insects. In the last decade of May, the total number of beetles in all test variants was relatively small, but, at the beginning of June, it increased almost to an equal extent. On the basis of flight traps, heavy damage of pods could be assumed, however, only a few larvae fell into traps on the soil surface, and virtually no damaged pods were detected. Thus the spraying with Fastac had no significant effects on the number of insects caught in traps.

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