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Plant resistance to insects offers apromising approach for managing chinchbugs and other insect pests affecting turf-grasses because it is sustainable and envi-ronmentally responsible. The overall goalof this research is to identify insect-resist-ant turfgrasses and investigate the mecha-nisms of this resistance. Knowledge ofspecific resistance mechanisms would bevaluable for identifying biochemical andphysiological markers for use ingermplasm enhancement programs, andfor characterizing plant defense strategiesto insect feeding.Selected cool- and warm-seasonturfgrasses were evaluated for resistance tochinch bugs in the Blissus complex undergreenhouse conditions. These studies haveidentified three vegetative buffalograsseswith moderate to high levels of resistanceto B. occiduus. Several zoysiagrasses andbermudagrasses were shown to exhibitmoderate resistance to chinch bugs. Thezoysiagrass ‘Emerald’ and bermudagrass‘Mini Verde’ displayed the highest level ofresistance; while the zoysiagrasses‘Meyer’, ‘Zenith’, and ‘DeAnza’, and thebermudagrasses ‘Jackpot’ and ‘Tifway’were moderately susceptible to chinch bugfeeding. All fine fescues evaluated weremoderately to highly susceptible to B. l.hirtus. This research demonstrates usefulvariation to chinch bug feeding amongbuffalograss, zoysiagrass, and bermuda-grass germplasm, and suggests the poten-tial to improve the resistance of these turf-grasses to B. occiduus and other chinchbug species.Another component of thisresearch is to determine if cool- and warm-season turfgrasses with resistance to B.leucopterus hirtus and B. insularis are alsoresistant to B. occiduus. Results fromthese studies suggest that cool- and warm-season turfgrasses with resistance to B. l.hirtus and B. insularis are also resistant toB. occiduus. Furthermore, chinch bug-sus-ceptible St. Augustinegrasses and fine fes-cues were moderately to highly resistant toB. occiduus. B. occiduus-resistant ('Prestige',formerly NE91-118) and -susceptible('378') buffalograsses were susceptible toall other chinch bug species. This researchclearly demonstrates multiple resistanceamong turfgrasses to chinch bugs and sug-gests different feeding mechanisms amongthe chinch bug complex. Studies are currently underway toexplore the feeding mechanisms of thesechinch bugs on the different turfgrassspecies. Specific studies include examin-ing the morphological features of chinchbug mouthparts, documenting probingbehaviors, and identifying chinch bugfeeding sites. Preliminary observationssuggest that no obvious differences in themouthpart morphology exist amongBlissus species and subspecies.Although the mechanisms associ-ated with chinch bug resistant turfgrassesare not well understood, photosyntheticmeasurements and enzyme kinetics exper-iments suggest photosynthetic compensa-tion in resistant turfgrasses. Resistant turf-grasses may be able to tolerate chinch bugfeeding by increasing their peroxidaseactivity. Resistant Turfgrasses for Improved Chinch Bug Management on Golf Courses Start Date: 2003Project Duration: three yearsTotal Funding: $20,000Tiffany Heng-MossUniversity of NebraskaObjectives:1. Evaluate selected cool- and warm-season turfgrasses for resistance to chinch bugs in the Blissus complex.2. Characterize the categories (antibiosis, antixenosis, and tolerance) of chinch bug-resistant turfgrasses. 3. Investigate the underlying biochemical and physiological mechanisms responsible for chinch bug resistance.The Blissus Complex: B. l. leucopterus (A), B. l. hirtus(B), B. insularis (C), and B. occiduus (D). Studies arecurrently underway to explore the feeding mechanismsof these chinch bugs on the different turfgrass species.2004 USGA Turfgrass and Environmental Research SummarySummary PointsThis research, which brings together astrong multidisciplinary team of entomol-ogists, turfgrass physiologists and breed-ers, and plant biochemists will contributeto our basic understanding of chinch bugresistance in turfgrasses.Several cool- and warm-seasons turf-grasses with resistance to chinch bugs inthe Blissus complex have been identified. Significant progress towards identify-ing the biochemical and physiologicalmechanisms responsible for chinch bug-resistance have been made.The identification of protein-mediatedmarkers for insect resistance provides anovel approach for screening insect-resist-ant germplasm. Ultimately, molecularmarkers identified from this research willprovide a set of tools for screening turf-grasses for resistance to chinch bugs andfurnish a starting point for characterizingadditional protein-mediated markers spe-cific to insect resistance.Knowledge gained from this projectwill benefit turfgrass sod producers, golfcourse superintendents and other turfgrassmanagers by furnishing turfgrasses withimproved resistance to chinch bugs. 32ABCDResistant turfgrasses (left) may be able to toleratechinch bug feeding by increasing their peroxidase activ-ity compared to susceptible turfgrasses

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