| Abstract | Krumpirova zlatica (Leptinotarsa decemlineata Say) najveći je štetnik krumpira u Hrvatskoj i svijetu. Moguće ju je suzbijati različitim metodama, međutim glavni način njenog suzbijanja je upotrebom insekticida. Zbog visokog biološkog potencijala i njene prirodne sposobnosti toleriranja i brzog prilagođavanja otrovima, primjetan je brz razvoj rezistentnosti na insekticide. Krumpirova zlatica rezistentna je na 56 djelatnih tvari insekticida te je do danas zabilježeno više 300 slučajeva rezistentnosti ovog štetnika. Do sredine 90-ih u Hrvatskoj se provodio sustavni monitoring rezistentnosti krumpirove zlatice. Pojava rezistentnosti na organofosforne insekticide (OP) dokazana je nakon 16 godina njihove šire primjene te je bila proširena na 70 % krumpirišta središnje Hrvatske. Na piretroide (P) rezistentnost je dokazana nakon sedam godina šire primjene te je bila proširena na 30 % krumpirišta istog područja. Navedene grupe insekticida ne preporučuju se za suzbijanje krumpirove zlatice već 20 godina te se postavlja pitanje jesu li populacije s rezistentnih područja još uvijek rezistentne na OP i P insekticide, te da li se pojavila rezistentnost na noviji insekticid tiakloprid (iz skupine neonikotinoida). U 2017. godini provedeni su laboratorijski pokusi u kojima se istraživala rezistentnost krumpirove zlatice na tri djelatne tvari insekticida (klorpirifos, cipermetrin, tiakloprid) na 16 lokaliteta središnje i sjeverozapadne Hrvatske. Utvrđena je učinkovitost preporučene doze, dvostruke, pola te 1/5 doze. Također, utvrđena je učinkovitost na laboratorijski uzgojen osjetljiv soj krumpirove zlatice s kojim su uspoređeni svi dobiveni podatci. Klasifikacija populacija provedena je prema IRAC metodi br. 1132 pri čemu su populacije klasificirane u 5 kategorija temeljem učinkovitosti (E) preporučene doze utvrđene 72 sata nakon tretiranja kao 1 – visoko osjetljive (E = 100%); 2 – osjetljive (100>E≥95%); 3 – blago rezistentne (95>E≥90%); 4 - rezistentne (90>E ≥50%); 5 – visoko rezistentne (E<50). Osjetljivi soj pokazao je očekivanu visoku osjetljivost na sve insekticide. Na cipermetrin osjetljiva je jedna populacija, jedna je blago rezistentna, većina populacija (13) su rezistentne, a jedna populacija je visoko rezistentna na cipermetrin. Dvije su populacije klasificirane kao osjetljive na klorpirifos, sedam populacija je rezistentno, a sedam populacija je visoko rezistentno. Pet populacija krumpirove zlatice rezistentno je na tiakloprid, a 11 njih je osjetljivo ili visoko osjetljivo. Iz rezultata je vidljivo da se situacija s rezistentnošću krumpirove zlatice na OP i P insekticide nije promijenila u odnosu na stanje prije 25 godina. Također, utvrđen je razvoj rezistentnosti i na novije korištenu djelatnu tvar iz skupine neonikotinoida što upućuje na vrlo brzo prilagodbu ovog štetnika na insekticide. |
| Abstract (english) | Colorado potato beetle (Leptinotarsa decemlineata, Say) is the biggest potato pest in Croatia and worldwide. It is possible to control it by various methods, however the main way of control is by the use of insecticides. Due to its high biological potential and natural ability to tolerate and quickly adapt to toxic substances, rapid development of resistance to insecticides is notable. Colorado potato beetle is resistant to 56 active ingredients of insecticides, and to date, more than 300 cases of resistance was registered. By he mid-1990s, systemic monitoring of CPB resistance was conducted in Croatia. The appearance of resistance to organophosphates (OP) has been proven after 16 years of their widespread use, and it has been spreaded on 70% of potato fields in central Croatia. Resistance to pyrethroids (P) has been proven after 7 years of their widespread use, and it has been spreaded on 30% of potato fields of that area. These groups of insecticides are not recommended for CPB control for the past 20 years, and the question is whether the populations from resistant areas are still resistant to OP and P insecticides, and whether the resistance to newer insecticide thiacloprid (from the neonicotinoid group) has occurred. In the year 2017, a laboratory experiment was set up to investigate the resistance of Colorado potato beetle to three insecticides (chlorpyrifos, cypermethrine, thiacloprid). Their efficiency was determined on 16 populations of beetles which were collected in central and north-western Croatia. Efficiency of recommended dose, double, half and 1/5 of the dose was determined. Efficiency of laboratory-grown susceptible CPB strain, to which all the obtained data were compared, was also determined. Rough classification of populations was conducted according to the IRAC method no. 1132 where populations were classified into 5 categories on the basis of the efficiency € of recommended dose determined 72 hours after treatment as: 1 – highly susceptible (E = 100%) ; 2 – susceptible (100>E≥95%) ; 3 – slightly resistant (95>E≥90%) ; 4 - resistant (90>E ≥50%) ; 5 – highly resistant (E<50). Susceptible strain showed the expected high susceptibility to both insecticides. One population was susceptible to cypermethrine, one was slightly resistant, 13 populations were resistant an one was highly resistant to cypermethrine. Two populations were classified as susceptible to chlorpyrifos, seven were resistant, and seven populations of CPB were highly resistant. Five populations of CPB were resistant to thiacloprid and 11 were susceptible or highly susceptible. Results of the experiment shows that the situation with CPB resistance to OP and P insecticides have not changed in relation to the condition 25 years ago. development of resistance to a newer active ingredient of insecticide from neonicotinoid group was also determined, indicating the rapid adaptation of this pest to insecticides. |
