Probing Stimulants from the Rice Plant towards the Smaller Brown Planthopper, Laodelphax striatellus (Fallen) (Homoptera: Delphacidae)

Abstract

When adult males of the smaller brown planthopper, Laodelphax striatellus were fed on 2% crude rice (leaf and stem ) extract containing 15% sucrose there were characteristic stylet sheaths deposited on parafilm membrane. Further bioassays with the butanol-soluble fr. of the extract revealed that it is highly effective for the insects. When the butanol fr. was charged on an ODS open column and eluted in sequence with 20, 40 and 100% m ethanol in w ater, the ODS-40% m ethanol fr. was shown as the most effective one. F urther separation of the ODS-40% methanol fr. resulted in six effective components. These components acted to stimulate very high probing response on L. striatellus only when they are combined. This activity was found to be similar to those of the ODS-40% methanol fr. and the original crude rice plant extract. Two of the active components were identified as tricin 5-O-glucoside and tricin 7-O-glucoside, respectively, through spectroscopic analyses.

Proteomics Coupled with Metabolite and Cell Wall Profiling Reveal Metabolic Processes of a Developing Rice Stem Internode

“…Esculetin has fungi-toxicity and may be involved in defense (Gomez-Vasquez et al, 2004). On the other hand, tricin 7-glucoside, a phagostimulant that triggers feeding in insects like the small brown planthopper (Adjei-Afriyie et al, 2000; Bouaziz et al, 2001), remained relatively low until the post-mature stage, when grains are fully mature.…”

Studies on probing stimulants for the green rice leafhopper, <i>Nephotettix nigropictus</i> (Stål) (Hemiptera: Cicadellidae), in the rice plant (<i>Oryza sativa</i> L.)

“…18) As an oligophagous insect, the GPLH requires one common and three specific flavonoid C-glycosides as probing stimulants. The SBPH, another oligophagous insect, also needed six components, including two common flavonoid O-glycosides (tricin 5-O-and 7-O-glucoside) 12) and four specific flavonoid C-glycosides (unpublished). The other oligophagous insect, the WBPH, also required one common tricin 5-O-glucoside 13) and three specific flavonoid C-glycosides (unpublished).…”

“…12) Each test treatment containing 1.0 g of a fresh rice plant equivalent (1.0 g eq.) extract solved with 2% sucrose solution (0.5 mL) was fed to the insect.…”

“…For instance, eight C-glycosylflavones were partially isolated from the rice plant as probing stimulants for the BPH. 10,11) Probing stimulants for the smaller brown planthopper (SBPH), Laodelphax striatellus, 12) and the white-backed planthopper (WBPH), Sogatella furcifera, 13) also were only partially reported. However, leafhoppers, including Nephotettix virescens, Nephotettix cincticeps and Nephotettix nigropictus, have scarcely been researched with regard to probing stimulants.…”

Evaluation of tricin, a stylet probing stimulant of brown planthopper, in infested and non‐infested rice plants

“…Tricin had an ecological function such as antifeeding and anti‐oviposition effect against the smaller BPH, Laodelphax striatellus (Fallen) (Adjei‐Afriyie et al. ). Tricin powders extracted from BPH‐resistant rice variety IR36 affected the mortality rate and the amount of honeydew produced by BPH nymphs and inhibited their oviposition and feeding behaviours (Ling et al.…”