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The phloem-feeding Southern chinch bug, Blissus insularis, harbors a high density of the exocellular bacterial symbiont Burkholderia in the lumen of specialized midgut crypts. Here we developed an organ culture method that initially involved incubating the B. insularis crypts in osmotically balanced insect cell culture medium. This approach enabled the crypt-inhabiting Burkholderia spp. to make a transition to an in vitro environment and to be subsequently cultured in standard bacteriological media. Examinations using ribotyping and BOX-PCR fingerprinting techniques demonstrated that most in vitro-produced bacterial cultures were identical to their crypt-inhabiting Burkholderia counterparts. Genomic and physiological analyses of gut-symbiotic Burkholderia spp. that were isolated individually from two separate B. insularis laboratory colonies revealed that the majority of individual insects harbored a single Burkholderia ribotype in their midgut crypts, resulting in a diverse Burkholderia community within each colony. The diversity was also exhibited by the phenotypic and genotypic characteristics of these Burkholderia cultures. Access to cultures of crypt-inhabiting bacteria provides an opportunity to investigate the interaction between symbiotic Burkholderia spp. and the B. insularis host. Furthermore, the culturing method provides an alternative strategy for establishing in vitro cultures of other fastidious insect-associated bacterial symbionts. [ABSTRACT FROM AUTHOR]

Understanding plant resistance mechanisms at a molecular level would provide valuable insights into the biological pathways impacted by insect feeding, and help explain specific plant tolerance mechanisms. As a first step in this process, we conducted next-generation sequencing using RNA extracted from chinch bug-tolerant and -susceptible buffalograss genotypes at 7 and 14 d after chinch bug feeding. Sequence descriptions and gene ontology terms were assigned to 1,701 differentially expressed genes. Defense-related transcripts were differentially expressed within the chinch bug-tolerant buffalograss, Prestige, and susceptible buffalograss, 378. Interestingly, four peroxidase transcripts had higher basal expression in tolerant control plants compared with susceptible control plants. Defense-related transcripts, including two peroxidase genes, two catalase genes, several cytochrome P450 transcripts, a glutathione s-transferase, and a WRKY gene were upregulated within the Prestige transcriptome in response to chinch bug feeding. The majority of observed transcripts with oxidoreductase activity, including nine peroxidase genes and a catalase gene, were downregulated in 378 in response to initial chinch bug feeding. The observed difference in transcript expression between these two buffalograss genotypes provides insight into the mechanism(s) of resistance, specifically buffalograss tolerance to chinch bug feeding. [ABSTRACT FROM AUTHOR]

Southern chinch bug, Blissus insularis Barber, is a severe pest of St. Augustinegrass throughout the southern United States. Host plant resistance is an environmentally friendly method to manage chinch bug infestations and is increasingly important, as the southern chinch bug develops resistance to insecticides. In this study, in an effort to understand resistance mechanisms in two varieties of St. Augustinegrass ('FX-10' and 'NUF-76'), we used the electrical penetration graph method to quantify stylet probing behaviors in two resistant and two susceptible St. Augustinegrass varieties. Overall, chinch bugs spent less time probing on resistant FX-10 and NUF-76 than on susceptible 'Floratam' and 'Palmetto', and individual probes were shorter in average duration but more numerous in resistant varieties than in susceptible varieties. During probing, chinch bugs spent more time in pathway-associated stylet activities (i.e., penetration through epidermal and mesophyll tissue) in the resistant varieties than in the susceptible varieties, likely indicating difficulty in finding and accessing an ingestion site. As a consequence, chinch bugs spent proportionately much less time engaged in xylem ingestion in both resistant varieties than in susceptible varieties but only in FX-10 were phloem-associated activities significantly reduced compared with those in susceptible varieties. We conclude that there is evidence for non-phloem-associated chinch-bug resistance factors in both NUF-76 and FX-10, and phloem-associated factors in FX-10. [ABSTRACT FROM AUTHOR]

St. Augustinegrass ( Stenotaphrum secundatum (Walter) Kuntze) is an economically important turfgrass in the southeastern United States. However, this turf species is prone to southern chinch bug, Blissus insularis Barber (Heteroptera: Blissidae) outbreaks. This insect is the most destructive pest of St. Augustinegrass wherever this turfgrass is grown. Host plant resistance has historically been an effective management tool for southern chinch bug. Since 1973, the 'Floratam' St. Augustinegrass cultivar effectively controlled southern chinch bug in the southeast. However, southern chinch bug populations from Florida and Texas have now circumvented this resistance, through mechanisms still unknown. Therefore, identifying and deployingnewcultivars with resistance to the southern chinch bug is imperative to combat this pest in an economically and environmentally sustainable manner. Currently, the number of cultivars with resistance against southern chinch bug is limited, and their efficacy, climatic adaptability, and aesthetic characters are variable. Hence, the main focus of this study is the identification of alternative sources of resistance to southern chinch bugs in previously uncharacterized St. Augustinegrass plant introductions (PIs) and its closely related, crossbreeding species, Pembagrass ( Stenotaphrum dimidiatum (L.) Brongniart). The PIs exhibited a wide range of responses to southern chinch bug feeding, as indicated by damage ratings. Damage ratings for seven PIs grouped with our resistant reference cultivars. Moreover, nine PIs exhibited antibiosis, based on poor development of southern chinch bug neonates, when compared with our susceptible reference cultivars. Altogether our study has produced strong support to indicate these materials are good candidates for future southern chinch bug resistance breeding in St. Augustinegrass. [ABSTRACT FROM AUTHOR]

The fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) is a potential biological control agent of hairy chinch bug, Blissus leucopterus hirtus Montandon (Hemiptera: Lygaeidae), but its virulence against this important turf grass pest is limited. To gain insight into why high numbers of conidia are needed for rapid kill, conidial persistence on insects was monitored under several experimental conditions. One day after exposure to a concentrated B. bassiana suspension, most conidia were removed from insects, particularly at warmer temperatures. Removal was higher when soil was present, suggesting that the insects may have transferred the conidia to soil. Most conidia on insects lost viability within 2 days. In contrast, conidia stored in soil under the same conditions as the insects remained viable. Earlier instar nymphs were more susceptible to lethal fungal infection than were adults. Materials recovered from a hexane rinse of adult insects inhibited conidial germination. These results have implications for applied aspects of chinch bug biological control with B. bassiana. [ABSTRACT FROM AUTHOR]

Fifteen buffalograss, Buchloe dactyloides (Nutt.) Engelm, genotypes and 94 diploid full-sib progeny were evaluated for western chinch bug, Blissus occiduus Barber (Hemiptera: Lygaeidae), resistance in two separate studies. The experimental design for each study was a completely randomized design. Adult chinch bugs were introduced onto caged single clone genotypes and progeny in the greenhouse. Chinch bug damage was assessed using a 1-5 visual damage rating scale with 1 = ≤ 10%; 2 = 11-30%; 3 = 31-50%; 4 = 51-70%; and 5 = ≥ 70% of the buffalograss leaf area with severe discoloration, or dead tissue. Highly significant differences were found among the genotypes and progeny for chinch bug damage. Among the genotypes, Legacy, Prestige, 184, 196, Bowie, NE 3297, NE 2769, and NE 2768 were moderately resistant with damage ratings of >1, but <3, while NE 2990, NE 2838, and 1-57-19 were moderately susceptible with damage ratings of ≥ 3, but <4. Among the progeny, one progeny (MP45) was highly resistant with a chinch bug damage rating of 1.0, 78 progeny (83%) had moderate resistance, with damage ratings of >1.0 and <3.0, 13 progeny (14%) were moderately susceptible with damage ratings ranging from 3.0 to 3.9, while only two were highly susceptible with damage ratings of ≥ 4.0. The significant variability among genotypes and progeny for chinch bug resistance indicates the ability to improve buffalograss resistance to chinch bugs through selection or hybridization of selected genotypes. [ABSTRACT FROM AUTHOR]

The southern chinch bug (Blissus insularis Barber) is the most damaging insect pest of St. Augustinegrass ( Stenotaphrum secundatum Walt. Kuntze), across the southern U.S.A. Susceptibility to the southern chinch bug and reproductive potential of the bugs on 24 cultivars from 7 genera in 8 turfgrasses were evaluated under greenhouse conditions. Stenotaphrum secundatum ('Raleigh', 'Texas Common', and 'Captiva') cultivars were the most susceptible among all the turfgrass genera and each produced populations ⩾ 97.5 bugs per 15-cm diameter plant within the 11-week test period from Jul to Sep 2008. Substantial populations also developed on zoysiagrass (Zoysia spp.) ('Emerald', 'Empire', 'Palisades', and 'Zorro') cultivars and on '609' buffalograss (Buchloë dactyloides (Nutt.) Engelm.). Low population development was recorded on cultivars of bermudagrass (Cynodon spp.), centipedegrass ( Eremochloa ophiuroides (Munro) Hack.), seashore paspalum ( Paspalum vaginatum Swartz), bahiagrass ( Paspalum notatum Flugge), and tall fescue ( Festuca arundinacea Schreb.). [ABSTRACT FROM AUTHOR]

The western chinch bug, Blissus occiduus Barber (Hemiptera: Blissidae), has emerged as a serious pest of buffalogra.ss, Buchloë dactyloides (Nuttall) Engelmann. In general, neonicotinoid insecticides effectively control a variety of turfgrass insects, particularly phloem-feeding pests. However, because of well documented inconsistencies in control, these compounds are generally not recommended for chinch bugs. This study was designed to document the contact and systemic toxicity of three neonicotinoid insecticides (clothianidin, imidacloprid, and thiamethoxam) to B. occiduns. In contact bioassays, thiamethoxam was ≈20-fold less toxic than clothianidin or imidacloprid to B. occidnus nymphs and three-fold more toxic to adults. In adult systemic bioassays, thiamethoxam was up to five-fold more toxic than clothianidin or imidacloprid. Interestingly, thiamethoxam was significantly more toxic to adults than to nymphs in both contact and systemic bioassays. This was not observed with clothianidin or imidacloprid. Bifenthrin, used for comparative purposes, exhibited 1,844-fold and 122-fold increase in toxicity to nymphs and adults, respectively. These results provide the first documentation of the relative toxicity of these neonicotinoid insecticides to B. occiduns. [ABSTRACT FROM AUTHOR]

The southern chinch bug, Blissus irzsularis Barber (Hemiptera: Blissidae), is the most destructive insect pest of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze. Management of B. insularts has depended on frequent insecticide applications, which has resulted in populations becoming resistant to several insecticide classes. To facilitate developing a resistance management program for this pest, it is necessary to develop methods to rear insects of known age, generation, and pesticide exposure history. Synchronized rearing methods were developed after testing five different laboratory methods. The use of glass jars and a combined diet of fresh corn, Zea mays L., cob and St. Augustinegrass proved to be best for producing B. insularis of known age and generation. Body size was consistent over nine generations of rearing. Production of a high proportion of brachypterous B. insularis (the nondispersal adult form) also suggests that populations were not stressed during laboratory rearing. This work presents the first successful synchronized rearing method for B. insularis. [ABSTRACT FROM AUTHOR]

The article presents a study on the resistance of grain pearl millet against the infestation of chinch bug, a piercing-sucking insect, in the U.S. The study intends to determine the degree of inheriting chinch bug resistance in pearl millet. The elite parental inbred lines were used as the subject in the study.

The cuticular sensory receptors that are found on the apex of the labium of hemipterans play an important role in their feeding behavior. In this study we describe the ultrastructure, number, and distribution of sensilla on the labium apex of the chinch bug, Blissus leucopterus leucopterus. Each apical field of sensilla on the labium contains 11 uniporous peg sensilla and one sensillum chaeticum. The uniporous peg sensilla are innervated by 4–5 bipolar neurons that send dendrites in the lumen of each peg. Three neurons are associated with each sensillum chaeticum, two neurons have dendrites in the lumen of the sensillum, and the third dendrite ends in a tubular body at the base of the sensillum. Behavioral tests that involve chemical blockage of the sensory receptors show the importance of the labial sensilla in feeding behavior. Both morphological and behavioral evidence indicate that the labial sensilla have a chemosensitive function. [ABSTRACT FROM AUTHOR]

The western chinch bug, Blissus occiduus Barber, has been documented as one of the most serious pests of buffalograss, Buchloë daclyloides (Nuttall) Engelmann, and zoysiagrass, Zoysia japonica Steudel, grown for turf in midwestern states. Resistance to the western chinch bug has been identified in both buffalograsses and zoysiagrasses. Choice and no-choice studies were conducted to determine the categories (antibiosis, antixenosis, and tolerance) of three resistant buffalograsses (PX3-5-1′, 196′, and 184′) and three resistant zoysiagrasses (El Toro, Emerald, and Zorro). Antibiosis studies found no significant differences in survival, nymphal development, or fecundity among the resistant and susceptible buffalograsses or zoysiagrasses, indicating that antibiosis is not an important factor in the resistance. Based on chinch bug damage ratings, 184, 196, and PX3-5-1 have comparable levels of tolerance to the known tolerant buffalograss 'Prestige', and Zorro was the most tolerant zoysiagrass. Choice studies indicated the presence of antixenosis in the buffalograss selection 196 and the zoysiagrass Emerald. [ABSTRACT FROM AUTHOR]

A 2-yr study was conducted to document the influence of selected buffalograss, Buchioë dactyloides (Nuttall) Engelmann, management practices (three mowing heights and five nitrogen levels) on the seasonal abundance of the western chinch bug, Blissus occiduus Barber (Heteroptera: Lygaeidae), and its beneficial arthropods. Vacuum, pitfall, and sticky traps samples were collected every 14 d from the middle of May through October from western chinch bug-resistant ('Prestige') and -susceptible ('378') buffalograss management plots. In total, 27,374 and 108,908 western chinch bugs were collected in vacuum and pitfall traps, respectively. More than 78% of all western chinch bugs were collected from the highly susceptible buffalograss 378. Significantly more bigeyed bugs (Geocoridae: Geocoris spp.) were collected from the 378 buffalograsss management plots than the Prestige plots. In contrast, buffalograss cultivar had little influence on the abundance of other beneficial arthropods collected. Statistically, western chinch bugs were least abundant at the lowest mowing height (2.5 cm) and increased in abundance with increasing fertility. Numerically, however, differences among management levels on western chinch bug abundance were minimal. Numerous beneficial arthropods were collected from buffalograss management plots, including spiders, predatory ants, ground beetles (Carabidae), rove beetles (Staphylinidae), bigeyed bugs, and several species of hymenopterous parasitoids. In general, beneficial arthropods were essentially unaffected by either mowing height or nitrogen level. Scelionid wasps represented 66.3% of the total parasitoids collected. The total number of scelionid wasps collected among the three mowing heights and five nitrogen levels were approximately equal. [ABSTRACT FROM AUTHOR]

The impact of Blissus occiduus Barber feeding on resistant ('Prestige') and susceptible ('378') buffalograsses, Buchloë dactyloides (Nuttall) Engelmann, was evaluated through measurement of carbon exchange rate, light and carbon assimilation (A-Ci) curves, chlorophyll a fluorescence, and nonstructural carbohydrates. No significant differences in carbon exchange rates were observed between infested and control plants for 378 at 5 and 10 d after infestation; however, at 20 d after chinch bug introduction, significant differences in carbon exchange rates between infested and control 378 plants were detected. Carbon exchange rates were similar between infested and control Prestige plants at 5, 10, and 20 d after infestation, suggesting that resistant plants can allocate energy for recovery from chinch bug injury. Significant differences in the photochemical efficiency of photosystem II (PSII) and the apparent photosynthetic electron transport ratio were observed between infested and control 378 plants, whereas, no significant differences in the photochemical efficiency of PSII and the electron transport ratio were detected between control and infested Prestige plants. Blissus occiduus-infested 378 and Prestige plants consistently had similar or higher levels of nonstructural carbohydrates compared with their respective control plants. These data suggest that both resistant and susceptible buffalograsses increase levels of nonstructural carbohydrates in response to B. occiduus feeding. This research also suggests compensatory photosynthesis takes place in Prestige but not in 378. [ABSTRACT FROM AUTHOR]

Chinch bugs are common pests of many agronomic and horticulturally important crops and turfgrasses. Previous research has indicated that some grasses exhibit resistance to multiple chinch bug species, whereas others are resistant to only one species. The objectives of this research were to document differences in the probing frequencies and locations among Blissus species as well as differences in mouthpart morphology as a first step in understanding the differential responses of grasses to chinch bug feeding. Scanning electron microscopy detected differences in the total lengths of proboscises as well as individual mouthpart segments among the four species studied. Blissus occiduus Barber probed significantly more often on buffalograss, Buchloë dactyloides (Nuttall) Engelmann, than any other plant material. Probing locations of B. occiduus and Blissus leucopterus leucopterus (Say) were similar on both B. occiduus-resistant and susceptible buffalograsses and KS94 sorghum, Sorghum bicolor (L.) Moench (B. occiduus-resistant, B. l. leucopterus-resistant). However, on 'Wheatland' sorghum (B. occiduus-resistant, B. l. leucopterus-susceptible), stylet tracts of B. l. leucopterus most often terminated in the bundle sheath cells, whereas those of B. occiduus generally terminated in the vascular tissues. [ABSTRACT FROM AUTHOR]

Choice and no-choice studies were conducted to determine the categories (antibiosis, antixenosis, and tolerance) of resistance of four buffalograsses (NE91-118, 'Bonnie Brae', 'Cody', and 'Tatanka') previously identified as resistant to the western chinch bug, Blissus occiduus Barber. Antibiosis studies found no significant differences in western chinch bug fecundity, nymphal development, or survival among the resistant and susceptible buffalograsses. Tolerance studies indicated that NE91-118, Cody, and Tatanka exhibited moderate-to-high levels of tolerance based on western chinch bug damage ratings and plant height, whereas Bonnie Brae exhibited moderate-to-low levels of tolerance. Choice studies indicated the presence of antixenosis in NE91-118, whereas Cody and Tatanka showed little or no antixenosis. Scanning electron microscopy was used to disclose morphological differences between NE91-118 (resistant) and '378' (susceptible). The epicuticular wax structures and trichome densities were similar between 378 and NE91-118, suggesting that morphological structures do not contribute to NE91-118 antixenosis. [ABSTRACT FROM AUTHOR]

Chinch bug [Blissus leucopterus leucopterus (Say.)] is the insect most likely to cause economic damage to pearl millet [Pennisetum glaucum (L.) R. Br.], a promising alternative feedgrain crop for the Southeast and Mid-South regions of the United States. In-furrow application of insecticide offers early season protection against chinch bug but may be phytotoxic. The insecticides that control early season infestations in other crops were evaluated for phytotoxic effects on pearl millet emergence and seedling growth under greenhouse conditions. Phorate caused the most phytotoxicity, reducing seedling emergence to less than 7% and shoot weight to 12 mg per seedling (17% of the non-treated control) at dose rates of 50.4 and 67.2 mg a.i. pot−1. Aldicarb, chlorpyrifos, and terbufos all caused some phytoxicity expressed by reduced seedling emergence. No phytotoxicity was observed with tefluthrin and tebupirimphos+cyfluthrin, either of which could be recommended for in-furrow application if effective against chinch bug on pearl millet. [Copyright &y& Elsevier]

The chinch bug, Blissus occiduus Barber, has been documented as a serious pest of buffalograss, Buchloë dactyloides (Nutall) Engelmann, and zoysiagrass, Zoysia japonica Steudel, turf grown in the Midwest. in addition to these two warm-season turfgrasses, several other warm-season grasses, including bermudagrass, Cynodon dactylon (L.) Pers., may also be at risk of B. occiduus infestations. This research evaluated selected bermudagrass and zoysiagrass cultivars for resistance to B. occiduus. Eleven zoysiagrass and four bermudagrass cultivars were evaluated for resistance to B. occiduus using no-choice studies under greenhouse conditions. Based on turfgrass damage ratings, the zoysiagrasses 'Diamond', 'Zoro', and 'Emerald', and bermudagrass 'Mini Verde' were identified as moderately resistant to B. occiduus. The zoysiagrasses 'Zenith', 'Meyer', and 'Crowne', and bermudagrasses 'Tifway 419' and 'Tifsport" were characterized as highly to moderately susceptible to B. occiduus. These results provide the first report of resistance to B. occiduus in zoysiagrass and bermudagrass germplasm. [ABSTRACT FROM AUTHOR]

The article focuses on a study regarding the impact of the parasitic wasp Eumicrocsoma benefica on the southern chinch bug, Blissus insularis' population in Florida. It states that 10 50 cm St. Augustinegrass were subjected to visual examination for the presence of chinch bugs using a microscope. Result show year round activity of the said parasite and its infestation in the chinch bug eggs. It adds that E. Benefica is an important factor in controlling the southern chinch bug populations.