Use of entomopathogenic nematodes for the management of western flower thrips and tospoviruses
Bennison J1, Maulden K1, Tomiczek M1, Morris J2, Barker I2, Boonham N2, Spence N2
1ADAS Boxworth, Boxworth,CB23 4NN,UK.
2Central Science Laboratory, Sand Hutton, York, Y041 1LZ, UK.
Correspondence: jude.bennison@adas.co.uk
Some of the major UK growers of chrysanthemums and other protected ornamental crops are using entomopathogenic nematodes (epns) for biological control of western flower thrips (WFT), Frankliniella occidentalis. Weekly foliar sprays of Steinernema feltiae (¡®Nemasys F¡¯ ®) are used throughout the life of the crop and these generally give good control of thrips. However, use of epns for thrips control is expensive and this is inhibiting more growers from adopting the technique. In addition, control on chrysanthemums can sometimes be inadequate during the summer when thrips pressure is high. Current Defra-funded research aims to fill gaps in knowledge on how epns control WFT populations and whether this control is sufficient to reduce the spread and severity of Tomato spotted wilt virus (TSWV) on chrysanthemums. Results indicate that epns reaching the growing medium during foliar application could play an important role in WFT control by killing the ground-dwelling thrips life stages. This information should enable the development of techniques to make the use of epns more effective and economic. In a glasshouse experiment, weekly foliar applications of ¡®Nemasys F¡¯ were made to two sequential crops of pot chrysanthemums, cv. ¡®Swing Time¡¯, which had been infested with viruliferous WFT larvae. The nematodes reduced mean numbers of WFT per plant, delayed plant infection with TSWV and reduced the symptom expression of TSWV.
