Feeding Behavior of Three Nephotettix Species (Homoptera: Cicadellidae) on Selected Resistant and Susceptible Rice Cultivars, Wild Rice, and Graminaceous Weeds

Abstract

The feeding behavior of Nephotettix virescens (Distant), Nephotettix nigropictus (Stal), and Nephotettix malayanus Ishihara & Kawase was monitored electronically on leafhopper-susceptible 'Taichung Native I' (TNl) and leafhopper-resistant 'Pankhari 203' and 'IR29' rice cultivars, on resistant wild rice (Oryza officinalis Well ex Watt, IRRI Accession No. 100896), and on the graminaceous weeds Leersia hexandra Swartz and Echinochloa glabrescens Munro ex Hook-F. During an access period of 180 min, the leafhopper adults fed in the phloem of the test plants for periods ranging from 4 to 92 min. Excretion of basic honeydew, which turned blue on filter paper treated with bromocresol green, and histological examination of insect salivary sheaths terminating in phloem tissues, also confirmed phloem feeding. The longer the phloem feeding, the greater was the quantity of basic honeydew excreted. Phloem feeding decreased on resistant rices, on the wild rice, and on weeds, but N. malayanus reared on L. hexandra fed longer in the phloem of this weed than did the other two species. Vulnerability of leafhopper-resistant cultivars to rice tungro viruses can be associated with insect ability to feed in the phloem. Having acquired tungro viruses from infected rice plants, the leafhoppers, particularly N. nigropictus, could transfer tungro viruses to weeds which become additional sources of virus inoculum.

Feeding behavior of the vectorDelphacodes kuscheli(Hemiptera: Fulgoromorpha: Delphacidae) on maize and oat

“…Th e excretion was collected on a 9 cm diameter Whatman fi lter paper disk placed around the base of seedlings which were enclosed in a cylindrical PET cage (20 cm high -9 cm in diameter). Papers were treated with 0.1 % nynhydrin in acetone and bromocresol green (Paguia et al 1980;Heinrichs et al 1985;Karim & Saxena 1991). For chemical analysis, honeydew droplets from the fi rst and second instars nymphs were collected from the plant surface with micropipettes.…”

“…Studies about feeding sites by means of salivary sheaths termination within plant tissues were recorded on important pests such as Saccharosydne saccharivora (Westwood) (Metcalfe 1969), Nilaparvata lugens Stål (Sogawa 1973(Sogawa , 1982Kimms 1989), Laodelphax striatellus Fallen (Sonku & Sakurai 1973) and Peregrinus maidis (Ashmead) (Fisk et al 1981). In addition the analysis of honeydew excretion was used as a complementary study of the feeding activity of planthoppers (Paguia et al 1980;Heinrichs et al 1985;Padgam & Woodhead 1988;Karim & Saxena 1991;Kumar et al 2001). Among other discussed issues, Mattson (1980) studied the eff ect of plant physiology on the insect feeding process and Hattori (2001) recorded the eff ect of nonhost antifeedant on the N. lugens behavior.…”

Characterization and Correlation of New Electrical Penetration Graph Waveforms for the Corn Leafhopper (Hemiptera: Cicadellidae)

“…Because the extent of insectÐplant contact (Alivizatos and Markham 1986) relates directly to pathogen acquisition and inoculation efÞciencies, and because such interaction lasts longer in plants suitable for insect feeding (Saxena 1969(Saxena , 1985, preferred host plants are exposed to higher pathogen pressures than are plants less accepted by insects (Saxena 1969(Saxena , 1985. Thus, control of leafhopper-transmitted pathogens, such as the rice tungro viruses, has relied mostly on insect-resistant cultivars that prevent successful insect feeding (Rezaul Karim andSaxena 1991, Azzam andChancellor 2002).…”

“…This approach can be effective for understanding the activities performed by hemipteran insects while probing (i.e., inserting or penetrating the stylets into the plant tissues; synonymous with stylet penetration; Backus 2000). For example, extensive research characterized the probing behavior of several Nephotettix species (Cheng and Pathak 1972, Heinrichs and Rapusas 1984, Rapusas and Heinrichs 1990, Rezaul Karim and Saxena 1991 and Nilaparvata lugens (Stål) (Khan and Saxena 1988, Kimmins 1989, Alam and Cohen 1998, Hattori 2001, important pests of rice, Oryza sativa L. In turn, this information has allowed detection and characterization of rice genotypes resistant to tungro disease (Azzam and Chancellor 2002).…”

Hitching a ride

“…Leafhoppers usually engage in phloem sap ingestion for only 5-30 min at a time but will occasionally ingest phloem sap for several hours. 84,96,99 The strategies that hoppers use during phloem sap ingestion are not entirely clear. The fact that they predominantly engage in sustained phloem sap ingestion for short periods of time, and that the stylets of some species are larger than the diameter of phloem sieve elements indicate that they may destroy these cells during their feeding process.…”