Abstract

Two of the most important plant protection problems in Swedish cucumber production are the European Tarnished Plant Bug (ETPB), and Cucurbit Powdery mildew (CPM). The control of the ETPB relies on Imidacloprid, a pesticide, which breaks down slowly and is harmful to beneficial insects. CPM fungi has begun to develop resistance to the commonly used fungicide (Imazalil) rendering its current use less effective. The main objective of this thesis was to evaluate alternative control methods for future incorporation into IPM strategies against ETPB and CPM using a participatory action research (PAR) approach. Towards this aim, two projects, tackling both of these problems were conducted in consultation between growers, researchers and advisors. The specific objectives of the ETPB project were to 1) compare responses of the ETPB to cucumber and candidate trap crops in olfactometer assays, 2) examine the responses of the ETPB to headspace volatile collections of candidate trap crops, 3) identify the attracting chemical compounds and 4) examine if sunflower could serve as a trap crop for ETPB in commercial cucumber greenhouses. The specific objectives of the CPM project were to 1) screen for effective alternative products against CPM and 2) to evaluate these, alone and in combination with Imazalil at different application intervals and in cultivars with different levels of resistance. The ETPB study showed that sunflower was more attractive than cucumber in greenhouse experiments but did not provide a sufficient level of control. In olfactometer assays, adults were more attracted to odours from flowering sunflower or lucerne than odours from flowering cucumber. Chemical analysis of plant odours showed a distinct differentiation between sunflower and cucumber. Sunflower exclusively released a number of monoterpenes and had an overall emission rate almost four times higher than cucumber. Therefore, it may be possible to use synthetic sunflower volatiles to attract ETPBs in the future. In semi-commercial CPM experiments, Sakalia, based on Reynoutria sachaliensis combined with Yuccah, a wetting agent, based on Yucca Schidigera, applied at 7-day intervals, consistently had the most suppressive effect, on CPM disease severity in two commercial cucumber cultivars. Further testing of this combination in commercial greenhouses is proposed to enable evaluation of the potential effects on yield and beneficial insects. The PAR approach took advantage of the knowledge and experience of researchers, advisors and growers and was seen as highly rewarding by all participants. Based on the results from this thesis, a potential future IPM strategy to control the major insect and fungal pests of cucumber is proposed.

Keywords

European tarnished plant bug; Lygus rugulipennis; Cucurbit powdery mildew; Podosphaera xanthii; Participatory action research; greenhouse cropping systems; Integrated pest management

Published in

ISBN: 978-91-576-9428-7, eISBN: 978-91-576-9429-4
Publisher: Department of Plant Protection Biology, Swedish University of Agricultural Sciences

SLU Authors

• Rur, Mira

  • Department of Plant Protection Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science
Horticulture


Permanent link to this page (URI)

https://res.slu.se/id/publ/77391