Temperature Thresholds and Degree-Day Model for \u3cem\u3eMarmara gulosa\u3c/em\u3e (Lepidoptera: Gracillariidae)

The developmental thresholds for Marmara gulosa Guillen & Davis (Lepidoptera: Gracillariidae) were investigated in the laboratory by using 17, 21, 25, 29, and 33°C. The lowest mortality occurred in cohorts exposed to 25 and 29°C. Other temperatures caused \u3e10% mortality primarily in egg and Þrst and second instar sap-feeding larvae. Linear regression analysis approximated the lower developmental threshold at 12.2°C. High mortality and slow developmental rate at 33°C indicate the upper developmental threshold is near this temperature. The degree-day (DD) model indicated that a generation requires an accumulation of 322 DD for development from egg to adult emergence. Average daily temperatures in the San Joaquin Valley could produce up to seven generations of M. gulosa per year. Field studies documented two, Þve, and three overlapping generations of M. gulosa in walnuts (Juglans regia L.; Juglandaceae), pummelos (Citrus maxima (Burm.) Merr.; Rutaceae), and oranges (Citrus sinensis (L.) Osbeck; Rutaceae), for a total of seven observed peelminer generations. Degree-day units between generations averaged 375 DD for larvae infesting walnut twigs; however, availability of green wood probably affected timing of infestations. Degree-day units between larval generations averaged 322 for pummelos and 309 for oranges, conÞrming the laboratory estimation. First infestation of citrus occurred in June in pummelo fruit and August in orange fruit when fruit neared 60 mm in diameter. Fruit size and degree-day units could be used as management tools to more precisely time insecticide treatments to target the egg stage and prevent rind damage to citrus. Degree-day units also could be used to more precisely time natural enemy releases to target larval instars that are preferred for oviposition

Identification of mutations conferring insecticide-insensitive AChE in the cotton-melon aphid, Aphis gossypii Glover

We have identified two mutations in the ace1 gene of Aphis gossypii that are associated with insensitivity of acetylcholinesterase (AChE) to carbamate and organophosphate insecticides. The first of these, S431F (equivalent to F331 in Torpedo californica), is associated with insensitivity to the carbamate insecticide pirimicarb in a range of A. gossypii clones. The S431F mutation is also found in the peach-potato aphid, Myzus persicae (Sulzer), and a rapid RFLP diagnostic allows the identification of individuals of both aphid species with a resistant genotype. This diagnostic further revealed the presence of S431 in several other pirimicarb-susceptible aphid species. The serine at this position in the wild-type enzyme has only been reported for aphids and provides a molecular explanation of why pirimicarb has a specific aphicidal action. A less specific insensitivity to a wide range of carbamates and organophosphates is associated with a second mutation, A302S (A201 in T. californica)

Seletividade de inseticidas usados na cultura da macieira a ovos de Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) Selectivity of insecticides used in apple orchards to eggs of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

Neste trabalho, foi avaliado o efeito de inseticidas sobre ovos de duas populações de Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae). O trabalho foi realizado em laboratório (25&plusmn;2&deg;C, UR de 70&plusmn;10% e fotofase de 12 horas) avaliando-se inseticidas, nas concentrações indicadas pelos fabricantes e/ou que estão em fase de pesquisa para o controle da mariposa-oriental, lagarta-enroladeira e mosca-das-frutas na cultura da macieira. Os produtos e dosagens (g ou mL do p.c. 100L-1 de água) avaliados foram: fosmet (Imidan 500 PM - 200), metoxifenozide (Intrepid 240 SC - 60), tebufenozide (Mimic 240 SC - 60), benzoato de emamectina (Proclaim 5 SG - 15), spinosad (Tracer 480 SC - 20), etofenprox (Trebon 100 SC - 150), clorpirifós etil (Lorsban 480 BR - 150) e testemunha (somente água). As pulverizações foram realizadas em ovos com até 12 horas de idade, utilizando-se torre de Potter. Avaliaram-se a viabilidade dos ovos, o período embrionário, e a sobrevivência das larvas de primeiro e segundo estádios provenientes dos ovos tratados. A toxicidade dos produtos foi determinada em função da mortalidade acumulada do predador durante o seu desenvolvimento, classificando-os conforme escala proposta pela IOBC. As duas populações de C. externa apresentaram o mesmo padrão de resposta aos produtos fitossanitários avaliados quando aplicados sobre ovos. Fosmet, metoxifenozide, tebufenozide, benzoato de emamectina, spinosad e etofenprox foram considerados inócuos, e clorpirifós etil levemente nocivo a ovos de C. externa, provocando a redução de 43,7% na viabilidade dos ovos e afetando em 20% a sobrevivência das larvas de primeiro estádio originadas dos ovos tratados.<br>The effect of some insecticides on eggs of two populations of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) were evaluated under laboratory conditions (25&plusmn;2&deg;C, RH of 70&plusmn;10% and 12 hours-photophase). The compounds were used at commercial or research concentrations used to control oriental fruit moth, leaf roller and fruit fly on apple orchards. The products and rates (g ou mL of formulated product 100L-1 of water) evaluated were: phosmet (Imidan 500 PM - 200), methoxyfenozide (Intrepid 240 SC - 60), tebufenozide (Mimic 240 SC - 60), emamectin benzoate (Proclain 5 SG - 15), spinosad (Tracer 480 SC - 20), etofenprox (Trebon 100 SC - 150) and chlorpyrifos (Lorsban 480 BR - 150), using water as control. Spraying of insecticides was on eggs (12 hours old) using the Potter tower. Survival and the period of the developmental stages were evaluated from treated eggs to the second-instar larvae, according to the IOBC recommendations. Both C. externa populations showed similar results for compounds applied. Phosmet, methoxyfenozide, tebufenozide, emamectin benzoate, spinosad and etofenprox were harmless, whereas chlorpyrifos was slightly harmful to C. externa, killing 43,7% of the eggs and 20% of the first-instar larvae from the treated eggs