A study on the variation of species diversity and sex ratio of thrips in winter wheat (Triticum aestivum L.) was conducted at the Lithuanian Institute of Agriculture (currently -Lithuanian Research Centre for Agriculture and Forestry). Assessments of thrips abundance were carried out from the beginning of tillering (growth stage (GS) 21) until complete maturity (Gs 89). Thirteen thrips species belonging to the three families were identified: 10 thrips species belonged to Thripidae, 2 to Phlaeothripidae and 1 to Aeolothripidae families. In terms of the feeding group, one species (Aeolothrips intermedius) belonged to zoophagous, the rest of the species were phytophagous. Frankliniella intonsa, F. tenuicornis, Haplothrips aculeatus and Limothrips denticornis were the earliest thrips species identified on winter wheat in spring. The dominating species were L. denticornis (41.3%), H. aculeatus (25.8%) and F. tenuicornis (20.5%). An average sex ratio of L. denticornis was 84.7%, and of H. aculeatus -68.2%, and of F. tenuicornis -71.1% and of F. intonsa -60.9%.

Abstract:Recently, considerable attention has been paid to climate change effects on nature and abundance of pests affecting agricultural crops. Our study was focused on the trends in aphid abundance during the growing seasons in spring barley in 1976-2007. Analysis was conducted based on the records of aphid abundance observations and detailed meteorological data.The first step in the study was to clarify the effects of temperature on aphid occurrence and abundance in spring barley. This part of the study was restricted to Dotnuva site, which is a typical area for commercial crop production, in order to reduce the influence of such effects as management, macroclimate, soil and others.A distinct and statistically significant increase in the mean air temperature was noted at the experimental site of the Lithuanian Institute of Agriculture in Dotnuva, Kedainiai for the period 1976-2007. A statically significant positive trend was identified for the mean air temperature during April-November. Consequently, during the last decade the occurrence of aphids has also become quite frequent.

) normomis. Imidokloprido ir pencikurono veikliųjų medžiagų mišinys, panaudotas bulvių beicavimui visomis tirtomis normomis, iš esmės mažina amarų ir kolorado vabalų kiekį ant bulvių kerų. Beicų normos neturi esminės įtakos amarų skaičiui ant lapų, kolorado vabalais apniktų kerų skaičiui ir kolorado vabalų kiekiui ant kero. Benomilas bei imidokloprido ir pencikurono mišinys efektyviai mažina bulvių pažeidimą šašais.Raktažodžiai: spragšiai, kolorado vabalai, amarai, šašai, bulvės, beicai ĮVADAS Spragšiai -polifaginiai kenkėjai, randami tiek že� mės ūkiui naudojamuose dirvožemiuose, tiek miš� ko dirvožemiuose (Khinkin, Nikolov, 1974; Koles� nikova, Taskaeva, Lapteva, Degteva, 2013;Kozina, Čačija, Igrs Barčić, Bažok, 2013 (Cate, 2007).Spragšių lervos dirvožemyje vystosi 2-5 me� tus. Daugiausia jų randama 10-12 cm gylyje (Arkhipov, 1979;Wilkinson, Finlayson, Campbell, 1977). Dauguma rūšių mėgsta drėgnesnį dirvo� žemį (Wightman, Morrison, 1978;Tsendsuren, 1979; Arkhipov, 1979), tačiau kai kurios spragšių rūšys nevengia net pusdykumių ir dykumų sąly� gų (Tsendsuren, 1979). Spragšių lervos pavasarį griaužia bulvių motininius gumbus ir požemines stiebų dalis, vėliau jaunus gumbus. Be tiesioginės žalos, jie dar atveria kelią įvairioms infekcijoms (Capinera, 2008).Ypač didelę žalą spragšiai kelia bulvėms ir ki� tiems augalams, sodinamiems po daugiamečių žolių (Kazankov, 1976;Lantinga, Oomen, Schiere, 2004;Erlichowski, 2008b (Geoffrion, Goix, 1978).