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A C Wallenhammar - One of the best experts on this subject based on the ideXlab platform.
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prevalence of plasmodiophora brassicae in a spring Oilseed rape growing area in central sweden and factors influencing soil infestation levels
Plant Pathology, 1996Co-Authors: A C WallenhammarAbstract:During 1986–87 the presence of clubroot in soils sampled from 190 fields was assessed using a bioassay method, based on baiting the soils with Brassica campestris spp. pekinesis cv. Granaat. Clubroot was detected in 148 (72%) of the fields investigated and, on average, 49.2% of the plants were infected according to the bioassay. Subsequent testing of fields in 1990 and 1992 (54 and 81 fields, respectively) where no further Brassica crops had been grown indicated a significant decrease in the degree of infestation to 7.1% in 1992. Clay soils showed, on average, the highest degree of infestation, and high infestation was recorded for a wide range of pH values (5.2–6.6). The highest degree of infestation was recorded on fields where Oilseeds were grown five times during the period 1965–85. The results presented show that, in a field with 100% infestation, the level of infestation declined to below the detection level after a period of 17.3 years. The half-life of the spore inoculum was determined to be 3.6 years. During the sensitivity testing of different Brassica species and cultivars, it was found that Chinese cabbage showed a low percentage of infestation in two soils, whilst some Oilseed rape and spring Oilseed Turnip rape cultivars showed high degrees of infestation in these soils.
Jürgens Sandra - One of the best experts on this subject based on the ideXlab platform.
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The suitability of cruciferous cultures to significant rapid pests and parasitoids
Eesti Maaülikool, 2018Co-Authors: Jürgens SandraAbstract:Magistritöö Maastikuhoolduse ja -kaitse õppekavalRapsi põldude külvipinnad suurenevad peaaegu iga aastaga, sest raps on oluline toidu- ja söödakultuur ning lisaks ka energiasäästliku kütuse tooraine. Kuid monokultuurid loovad head elupaigad rapsikahjuritele ning ei lase looduslikel vaenlastel esile pääseda. Pikkade mürgitamiste tagajärjgedel on hakanud kujunema mürgiresistentsed putukad ning taimedesse jäävad pestitsiidide jäägid. Seetõttu on vaja leida loodussõbralikke taimekaitsestrateegiaid, mille üheks meetodiks on püünistaimede kasutamine. Katse viidi läbi Eesti Maaülikooli katsepõldudel Tartus, Eerikal 2017 aasta suvekuudel. Katseala koosnes 12st katselapist, igaüks suurusega 4 m2 . Iga lapi ümber oli 1 meetri laiune taimikuta eraldusriba. Katses oli kokku neli erinevat kultuuri – suviraps, paksoi, suvirüps ja õlirõigas. Ristõielised külvati lappidele 8. mail. Putukate kogumine algas 12. juuni ning korjamine toimus iga 7 päeva tagant. Uurimistöö tulemustest selgus, et katses peamised kahjurid olid naeri-hiilamardikas (vastsed ja valmikud) ning kapsa-tuhktäi. Selgus, et paksoi sobib kõige paremini rapsile püünistaimeks. Katse andis potentsiaalsete püüniskultuuride osas lootusandvaid tulemusi. Nende rakendamine rapsi kaitseks aitaks vältida keemiliste tõrjevahendite kasutamist, mis omakorda soodustaks rapsikahjurite parasitoidide arvukust. Uuringuid tuleb jätkata põldkatsetes, et põllumeestele saaks anda põhjendatud soovitusi, kuidas ja kelle vastu püüniskultuure kasutada.Rapeseed fields are increasing almost every year because rape is an important food and feed culture, rape is also a good material for energy-saving fuel. Monocultures create good place for rape pests and prevent natural enemies from gaining access. The effects of longterm poisoning have developed poison-resistant insects and residues of pesticides may remain in plants. Therefore, it is necessary to find environmentally friendly plant protection strategies, one of which is the use of trapping plants. The experiment was hold in 2017 summer months in The Estonian University of life sciences test field in Eerika.The test field consisted of 12 testbeds, each with a size of 4 m2 . Every testbed was surrounded by a 1 metre space. The test had four cultures: rape, pak-choy, Oilseed radish and Oilseed Turnip. The cruciferous crops were planted on the 8 of May. The collection of insects began on June 12, and picking was carried out every 7 days. The results of the research revealed that in the experiment, the main pests were pollen beetles (larvae and imago) and cabbage aphids. It turned out that pak-choy can be a major trapper for rapeseed key pests. The experiment gave hopeful results for potential trap crops. Their application for the protection of rape would help to prevent the use of chemical pesticides. Studies should be continued in field tests, that we could give farmers substantiated recommendations on how and against whom to use trapping plants
