Volatiles in perennial ryegrass infected with strains of endophytic fungus: impact on African black beetle host selection. (6th June 2014)

• Record Type: Journal Article
• Authors: Qawasmeh, A.; Raman, A.; Wheatley, W.
• Is Part Of: Journal of applied entomology. Volume 139:Number 1/2(2015)
• Page Start: 94
• Page End: 104
• Publication Date: 2014-06-06
• Subjects: Entomology -- Periodicals; Insect pests -- Periodicals; 595.7
• DOI: 10.1111/jen.12140
• Languages: English
• ISSNs: 0931-2048

Abstract

<abstract abstract-type="main" id="jen12140-abs-0001"> <title>Abstract</title> <p>Perennial ryegrass (<italic>Lolium perenne</italic>) is often infected with the fungal‐endophyte <italic>Neotyphodium lolii</italic>. In addition to the 'wild‐type' strain (E<sup>WT</sup>), several 'selected' strains of <italic>N. lolii</italic> are now being marketed as AR1 (E<sup>AR1</sup>) and AR37 (E<sup>AR37</sup>). Each of these strains impact positively on <italic>L. perenne</italic>'s resistance against many insects, including the African black beetles (<italic>Heteronychus arator</italic>). The impact of volatile oils produced specifically by each strain in the endophyte–grass association in enhancing the grass's resistance to insects is still largely unknown. Keeping these in view, we determined the volatile oil profiles produced by <italic>L. perenne</italic> infected with either E<sup>WT</sup> or E<sup>AR1</sup> or E<sup>AR37</sup> and determined the impacts of these volatiles on the host‐selection behaviour of <italic>H. arator</italic> adults. In the absence of endophyte infection (E<sup>–</sup>), <italic>L. perenne</italic> produced 18 different volatile oils. In <italic>L. perenne</italic> E<sup>WT</sup>, quantities of 2‐ethyl‐1‐hexanol acetate (Rt = 14.5 min), (<italic>Z</italic>)‐2‐octen‐1‐ol (Rt = 22.2 min), and butylated hydroxyl toluene (Rt = 23.2 min) were 24, 16 and 26%, respectively, greater than <italic>L. perenne</italic> E<sup>–</sup>. The strains E<sup>AR1</sup> and E<sup>AR37</sup> affected differently the quantities of the volatile compounds but not their identity. In the four‐choice bioassay, males and females of <italic>H. arator</italic> were equally attracted to each strain. In Y‐tube olfactometer, compared against E<sup>–</sup>, <italic>H. arator</italic> adults were less attracted to <italic>L. perenne</italic> E<sup>WT</sup> and E<sup>AR1</sup>. The attractiveness of E<sup>AR37</sup> was similar in effect to E<sup>–</sup> to <italic>H. arator</italic>. The results indicate that each strain of <italic>N. lolii</italic> alters the profile of volatile oils in <italic>L. perenne</italic> differently and that alteration can influence <italic>H. arator</italic> adult‐host selection.</p> </abstract>