Pesticide dissipation curves in peach, pear and tomato crops in Uruguay.

Dissipation curves of azoxystrobin and of the neonicotinoids acetamiprid and thiacloprid in peach; azinphos-methyl and carbaryl in pear and azoxystrobin, chlorfenapyr and chlorpyrifos in high-tunnel tomato crops were studied in the Southern region of Uruguay. An analytical methodology based on solid phase extraction (SPE) and detection by High Performance Liquid Chromatography with Diode Array Detector (HPLC/DAD) was used for acetamiprid and thiacloprid. Coupled SPE and detection by Gas Chromatography with Mass Selective Detector (GC/MSD) was used for the detection of azinphos-methyl, azoxystrobin, carbaryl, chlorfenapyr and chlorpyrifos residues. Curves were modeled mathematically with Solver program of Microsoft Excel. The best fit for acetamiprid and thiacloprid in peach was achieved with the exponential model (r(2)=0.961 and 0.944, respectively). In the case of peach fruits there is not a Maximum Residue Limit (MRL) for acetamiprid in the Codex Alimentarius, while 0.5 mg/kg is the value rated for thiacloprid. The MRLs accepted by the European Union (EU) are 0.1 mg/kg for acetamiprid and 0.3 mg/kg for thiacloprid. According to the curves determined in these experiments, thiacloprid residues 10 to 12 days after application (daa) were below the MRLs established by both sources. In the case of acetamiprid, 25 daa would be required, according to the exponential mathematical model, to get residues levels below the MRL values established by the EU. For azinphos methyl in pear, the residues detected were mathematically fitted to an exponential model (r(2)=0.999). According to it, residue levels under the MRL established by the EU (0.05 mg/kg) are gotten in our conditions in 20 daa. In plastic tunnel tomato chlorfenapyr residues were not detected from 16 daa, having the dissipation curve an exponential trend. In the same condition, there was not a decay of the azoxystrobin concentration during a 24-day trial, being it around 0.40 ± 0.05 mg/kg.

Atração de machos da lagarta-das-fruteiras Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae) aos componentes do feromônio sexual sintético na cultura do caquizeiro / Attraction of males of the South American tortricid moth Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae) to the components of the synthetic sexual pheromone in persimmon

A lagarta-das-fruteiras Argyrotaenia sphaleropa (Meyrick) tem causado prejuízos significativos em frutíferas cultivadas no Sul do Brasil com destaque para o caquizeiro, pessegueiro e videira. Neste trabalho, apresenta-se a resposta de machos de A. sphaleropa a diferentes formulações e doses do feromônio sexual sintético e a longevidade das formulações mais eficientes no campo. As formulações contendo Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1), Z11,13-14Al + Z11,13-14Ac (9:1) e Z11,13-14Ac + Z11,13-14Al (9:1) (1,0 mg/septo) foram as mais eficientes na captura de machos quando comparadas com fêmeas virgens. A dose de 1,0 mg/septo foi significativamente superior a 0,1 mg na captura de A. sphaleropa para as três formulações. A formulação Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1), na dose de 1,0 mg/septo, foi eficiente por pelo menos 75 dias, enquanto que a Z11,13-14Ac + Z11,13-14Al (9:1) por até 60 dias. Para futuros trabalhos visando o monitoramento de A. sphaleropa com feromônio sexual na cultura do caquizeiro, recomenda-se o emprego das formulações Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1) na dose de 1,0 mg/septo, substituindo os septos de borracha a cada 75 dias.

Argyrotaenia sphaleropa (Meyrick) has been leading to significative damage in cultivated fruits such as persimmon, peach and grape in Southern Brazil. In the present work, the response of A. sphaleropa males to different formulations and doses of the synthetic sexual pheromone was evaluated, as well as the duration of the most efficient formulations under field conditions. Formulations containing Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1), Z11,13-14Al + Z11,13-14Ac (9: 1) and Z11,13-14Ac + Z11,13-14Al (9: 1) (1.0 mg/ dispenser) were the most efficient as male attractants when compared to unmated females. The concentration of 1.0 mg/ dispenser was significantly more attractive than the 0.1 mg/ dispenser for the three formulations. The formulation Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1), at 1.0 mg/dispenser, was efficient for at least 75 days, while the attractiveness of Z11,13-14Ac + Z11,13-14Al (9:1) lasted 60 days. Further field experiments should employ the formulation Z11,13-14Ac + Z11,13-14Al + Z11-14Al (4:4:1) at 1.0 mg/dispenser, being dispensers replaced at 75-days intervals.