Osetljivost repičinog sjajnika (Meligethes aeneus F.) na insekticide različitih mehanizama delovanja i mogućnost suzbijanja

Abstract

Repičin sjajnik (Meligethes aeneus F.) je najštetnija insekatska vrsta u usevima ozime uljane repice u svetu i kod nas. Najveće štete nanose imaga koji tokom ishrane oštećuju cvetne pupoljke u potpunosti izjedajući cvetne elemente. Monitoring populacija M. aeneus nа usevimа uljаne repice u Srbiji vršen je tokom trogodišnjih ogleda (2008-2010. godine) nа osnovu vremenа nаseljаvаnjа usevа uljаne repice i brojnosti imаgа u osetljivim fenofаzаmа rаzvojа usevа uljаne repice. U radu su primenjene metode sakupljanja pomoću žutih vodenih klopki i otresanja imaga sa vršnih cvasti uljane repice. Rezultati su pokazali da repičin sjajnik naseljava usev ozime uljane repice u fenofazi porasta stabla (BBCH 30-31), a da najveću brojnost ostvaruje u fenofazi zeleno-žutih pupoljaka (BBCH 57-59). U svim lokalitetima i godinama istraživanja brojnost imaga repičinog sjajnika prelazila je ekonomske pragove štetnosti. Najveća brojnost postignuta je u lokalitetu Kovin, zatim u lokalitetu Smederevo, a u lokalitetu Požarevac brojnost je bila najniža. Obzirom da gajenje uljane repice za sobom povlači i primenu insekticida za suzbijanje repičinog sjajnika, u radu je tokom trogodišnjih poljskih ogleda proučavana efikasnost insekticida rаzličitih mehаnizаmа delovаnjа: piretroidа (lаmbdа-cihаlotrin, аlfа-cipermetrin, bifentrin), orgаnofosfаtа (pirimifos-metil), kombinаcije orgаnofosfаtа i piretroidа (hlorpirifos + cipermetrin) i neonikotinoidа (tiаkloprid) na imaga M. aeneus. Komercijalne formulacije insekticida su primenjivаne u preporučenim dozаmа u usevima ozime uljаne repice u vreme vidljivih cvetnih pupoljaka, ali još zatvorenih (BBCH 55-57). Efikasnost piretroida i organofosfata je tokom svih ogleda bila od 90- 100%, a neonikotinoida od 85-95%, pa se zbog ispoljene visoke efikasnosti može preporučiti njihova primena u Srbiji. Osetljivost M. aeneus prema navedenim insekticidima je ispitana korišćenjem testa nanošenja insekticida na zidove posuda - Adult Vial Test i testa potapanja cvetnih pupoljaka uljane repice - Dipping test. U radu su osim preporučenih korišćene i smanjene doze insekticida (75, 50, 25, 10 i 5%). Dobijeni rezultati su pokazali da nije došlo do pojave rezistentnosti jer su imaga ispitivanih populacija M. aeneus ispoljila visoku osetljivost na sve ispitivane insekticide. Najveći mortalitet je beležen 24 sata posle tretmana. Prema kriterijumima za ocenu osetljivosti repičinog sjajnika na insekticide, testirane populacije se svrstavaju u drugu grupu tj. osetljive. Populacija iz lokaliteta Kovin se pokazala kao najmanje osetljiva. Određivanjem ukupnog sadržaja i koncentracija citohrom P450 monooksigenaza potvrđena je normalna osetljivost repičinog sjajnika na primenjivane insekticide.

Pollen beetle (Meligetes aeneus F.) is the most damaging insect species in winter oilseed rape fields worldwide. The insect adults cause the greatest damage by feeding on the flower buds eating their parts entirely. M. aeneus population was monitored in the oilseed rape crops in Serbia during three year long period (2008 - 2010) by recording a moment of the crop infestation and number of adults in susceptible oilseed rape growth phases. During the experiments insects were collected by using yellow water traps and by shaking off the insects from the top flower clusters. The results showed that a pollen beetle inhabits an oilseed rape crop in the stem growth pheno-phase (BBCH 30-31) and reaches its population peak at the green-yellow bud phase (BBCH 57 – 59). In all the localities and the years of observation the population of pollen beetle adults exceeded the economic threshold. The highest population was recorded in the locality of Kovin, then Smederevo, and the lowest in Požarevac. Since a pollen beetle is usually controlled by application of insecticides, it was studied efficacy of some insecticides with different modes of action: pyrethroids (lambda-cyhalothrin, alpha-cypermethrin, bifenthrin), oganophosphate (pyrimifosmethyl), combination of oganophosphate and pyrethroid (chlorpyrifos + cypermethrin) and neonicotinoide (thiaclopride) on M. aeneus adults in three-year field experiments. The insecticides were applied according to the producer’s recommendation in the oilseed rape winter crops at the moment of visible but still closed flower buds (BBCH 55-57). In all the experiments efficacy of pyrethroids and organophosphates ranged from 90 to 100%, and neonicotinoide from 85 to 95%. Therefore, they can be recommended for use in a pollen beetle spraying program in Serbia. Susceptibility of M. aeneus to the insecticides was tested by the methods of insecticide deposition on test vial walls – Adult Vial Test, and by submerging oilseed rape flowers – Dipping test. Besides the recommended insecticide doses, it was tested several decreased rates (75, 50, 25, 10, 5%) of the recommended value. The obtained results showed no occurrence of the resistance since adults of the insect showed high susceptibility to all the insecticides tested. The highest mortality was recorded 24h after the treatments. According to criteria for evaluation of pollen beetle susceptibility to insecticides, the tested insect population belongs to the second group i.e. susceptible. Population from the Kovin locality was the least susceptible. By the determination of the total content and concentration of cytochrome P450 mono-oxygenase, it was confirmed normal susceptibility of pollen beetle to the insecticides.