Barbosa, L. R.

do Valle, Cacilda Borges

Oliveira, M. C. M.

Rabaiolli, M.

Valério, José R.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Screening Brachiaria Hybrids for Resistance to the Pasture Spittlebug Notozulia entreriana (Berg, 1879) (Hemiptera: Cercopidae) in Central Brazil José R. Valério EMBRAPA, Brazil L. R. Barbosa CNPq/Fundect, Brazil Cacilda Borges do Valle EMBRAPA, Brazil M. Rabaiolli CNPq/Fundect, Brazil M. C. M. Oliveira AGRAER, Brazil Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/12-2/13 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]394　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems——— Developing Improved PlantsScreening Brachiaria hybrids for resistance to the pasture spittlebug Notozulia entreriana(Berg ,1879) (Hemiptera :Cercopidae) in central BrazilJ . R . Valério 1 ; L . R . Barbosa2 ; C . B . do V alle1 ; M . Rabaiolli3 ; M . C . M . Oliveira4 .1 Embrapa Bee f Cattle , P .O . Box 154 , Campo Grande , MS , 79002‐970 , Braz il . E‐mail : j raul ＠ cnp gc .embrapa .br ;2 CN Pq/ Fundect PhD scholar ; 3 CN Pq / Fundect BS scholar ; 4 AGRA ER .Key words : antibiosis ,forage grass ,froghopper ,host plant resistance ,pasture pestsIntroduction The beef cattle industry in tropical America , with its extensive production systems , depends on forage grasses formeat production . Several species of the genus Brachiaria comprise the most important of these grasses . Because of theirexcellent adaptation , particularly of B . decumbens to low‐fertility acid soils , they have been widely adopted throughout Centraland South America . The extensive monoculture of B . decumbens , however , has favored the buildup of several spittlebugspecies , the most damaging pests of Brachiaria in tropical America . These insects can drastically reduce plant grow th , drymatter production as well as forage quality (Valério et al . ,２００１) . A great effort has been devoted to finding grasses resistantto spittlebugs . The objective of the present work was to evaluate ２８ hybrids of the genus Brachiaria , from the germplasmavailable at Embrapa Beef Cattle Research Center , for resistance to the spittlebug Notoz ulia entreriana using the selectioncriteria of nymphal survival and nymphal period .Material and method The assay was conducted in the greenhouse ( T ＝ ２８畅０ ± ２畅２ ℃ and RH ＝ ７１畅７ ± ８畅８％ ) using methodologydescribed by Lapointe et al . (１９８９) . The hybrids were initially established in a hydroponic system ( a minor modification in theoriginal methodology) , then planted in small plastic cups and , posteriorly transferred to １７ cm diameter plastic pots . Each ofthese pots were covered with aluminum tops , which have a central opening for the grass stems . This is done in order tostimulate abundant superficial rooting at the soil surface and hence provide enough feeding sites for the newly hatched nymphs .The plants were infested two and half months af ter planting with five eggs [obtained according to Valério (１９９３ ) ] per pot .There were ten replications for each hybrid in a complete randomized assay . Close to adult emergence , the pots wereindividually caged . The emerging adults were collected daily . As screening criterium , only the hybrids presenting ,simultaneously , percentage of nymphal survival below the average for the group , minus the correspondent standard deviationand , nymphal period above the average for the group plus the respective standard deviation , were selected as resistant . B .decumbens cv . Basilisk was included as the susceptible check whereas B . briz antha cv . Marandu , as the resistant one .Results and discussion The survival rates varied from １２％ to ９６％ , the average being ７６ ± １５畅６％ for the group . For nymphalperiod , the variation was from ２６畅９ to ３７畅５ days , with an average of ３０畅８ ± ２畅３ days . In accordance with adopted screeningcriterium , two hybrids ( HB３３１ and HB３３６ ) were selected as more resistant in this trial . The nymphal survival for thesehybrids were , respectively , １２％ and ４８畅９％ ; whereas the duration of the nymphal period were , respectively , ３７畅５ and ３３畅７days . Presumably the resistance exhibited by these plants is due to secondary chemicals , being still necessary , additionalstudies to fully understand the basis of this resistance . All the remainder evaluated hybrids provided high nymphal survivorship(７９畅２ ± ７畅５％ ) , showing , therefore , suitableness as host plant to this spittlebug species .Conclusions Two Brachiaria hybrids were selected as resistant to the pasture spittlebug Notoz ulia entreriana through themechanism of resistance termed antibiosis , impairing development and survival of the nymph . Aiming to release new spittlebugresistant Brachiaria cultivars , however , both hybrids should also be evaluated with sugarcane spittlebugs of the genusMahanarva ( serious threat to forage grass in Northern Brazil) , additionally to complementary agronomic evaluations in multi‐location trials in distinct ecosystems of the country .ReferencesLapointe , S .L . ; Sotelo , G . ; Arango , G . , １９８９ . Improved technique for rearing spittlebugs ( Homoptera : Cercopidae) . J .Econ . Entomol .８２ (６ ) :１７６４‐１７６６ .Valério ,J .R . ,１９９３ . Spittlebug ( Homoptera : Cercopidae) Egg Production on Agar‐Water Substrate . A n . Soc . Entomol .Brasil , ２２(３) :５８３‐５９０ .Valério ,J .R . ,Cardona ,C . ;Peck ,D .C . ;Sotelo ,G . ,２００１ . Spittlebugs : bioecology , host plant resistance and advances inIPM . Proceedings X IX International G rassland Congress , Piracicaba , Braz il , FEA LQ , ２００１ . ２１７‐２２１ .Funding sources EMBRAPA‐CNPq/ FUNDECT /MS‐UNIPASTO

Screening \u3ci\u3eBrachiaria\u3c/i\u3e Hybrids for Resistance to the Pasture Spittlebug \u3ci\u3eNotozulia entreriana\u3c/i\u3e (Berg, 1879) (Hemiptera: Cercopidae) in Central Brazil

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=3318&amp;context=igc

Screening \u3ci\u3eBrachiaria\u3c/i\u3e Hybrids for Resistance to the Pasture Spittlebug \u3ci\u3eNotozulia entreriana\u3c/i\u3e (Berg, 1879) (Hemiptera: Cercopidae) in Central Brazil

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