ANDRE RICARDO MACHI
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Artigo IPEN-doc 23556 Milbemectin and etoxazol acaricide resistant and susceptible strains of Tetranychus urticae (Trombidiformes: Tetranychidae) are equally radiosusceptible and unable to reproduce when irradiated with 400 Gy2016 - ARTHUR, VALTER; NICASTRO, ROBERTO L.; SATO, MARIO E.; MACHI, ANDRE R.The twospotted spider mite, Tetranychus urticae Koch (Trombidiformes: Tetranychidae), is considered one of the most important phytophagous mites causing considerable damage in several agricultural crops. The aim of this study was to evaluate the susceptibility to gamma irradiation of strains of T. urticae resistant (R) and susceptible (S) to the acaricides, milbemectin and etoxazol. The R and S strains for milbemectin and etoxazol were irradiated with 200 and 400 Gy of gamma radiation in a Gammacell 220 source to evaluate the effects of gamma radiation on the growth rate of the mites. A dose of 400 Gy totally eliminated populations of both R and S strains of T. urticae within 10 d. A dose of 200 Gy was not sufficient to totally eliminate both T. urticae strains, but it significantly reduced egg viability of both strains. In the most likely measure of efficacy for phytosanitary irradiation of mites—i.e., prevention of F1 egg hatch when parent adults are irradiated—no differences were found in response to irradiation among the 4 strains.Artigo IPEN-doc 23551 Irradiation of Ecdytolopha aurantiana (Lepidoptera: Tortricidae) pupae in oxygen requires a lower dose to strongly reduce adult emergence and prevent reproduction than irradiation in air2016 - ARTHUR, VALTER; ARTHUR, PAULA B.; MACHI, ANDRE R.The purpose of this research was to determine if γ-irradiation of lepidopteran pupae in oxygen would have a greater effect in either preventing adult emergence or in the successful development of F1 life stages than γ-irradiation of pupae in air. Pupae of the citrus fruit borer, Ecdytolopha aurantiana (Lima) (Lepidoptera: Tortricidae), were irradiated in either 100% oxygen or in normal air. In each experiment, thirty 10 d-old pupae of E. aurantiana in each of 4 replicates were treated with either 0, 100, 200 or 300 Gy of γ radiation. After irradiation the percent emergence of adults, and the percent viability of F1 eggs and larvae were compared with the corresponding results of irradiation in air. The results showed that irradiation of the pupae in pure oxygen significantly reduced the adult emergence and egg hatch compared to irradiation of the pupae in air. Thus irradiation in oxygen of pupae with 300 Gy completely prevented emerged adults from producing eggs. Therefore, irradiation of E. aurantiana pupae with 300 Gy in oxygen is a viable candidate as a phytosanitary treatment. In contrast, irradiation in air of pupae with 300 Gy resulted in 5% egg hatch, although 100% of these larvae died as first or second instars. Therefore based on the criterion of 100% mortality of F1 larvae, 300 Gy in air can also be considered to be a viable candidate for a phytosanitary treatment. These results indicate that the dose required for (PI) treatment may be reduced by increasing the oxygen gas content in fruit packages or containers.Artigo IPEN-doc 23543 Oxygen atmosphere potentiates radiation effects on Brevipalpus yothersi (Trombidiformes: Tenuipalpidae)2016 - MACHI, ANDRE R.; ARTHUR, VALTERThe objective of the study was to compare the effect of pure oxygen to that of ambient air on gamma irradiation of Brevipalpus yothersi (Baker) (Trombidiformes: Tenuipalpidae). Flasks containing the mites were irradiated in a Gammacell-220 irradiator with Cobalt-60 emitting gamma radiation at a rate of 381 Gy/h. Seventy mites per flask replicated 4 times were irradiated in either pure oxygen or air with 0 (control), 200, 230, 270, or 300 Gy as the intended doses. All eggs, deutonymphs and adults were counted each day and the parameters of egg production, egg hatch, development and mortality were recorded. Data were analyzed with ANOVA and means were separated with Tukey’s Honestly Significant Difference (HSD) test at 5% probability. Generally, irradiation of females with progressively larger doses—whether in oxygen or in air—resulted in progressively greater negative biological effects, and these effects were greater when females were irradiated in oxygen than in air. Non-irradiated gravid females exposed to pure oxygen deposited 79.3 ± 0.3 eggs per female compared to 73.0 ± 0.3 per female in ambient air. The numbers of eggs oviposited by females irradiated with the largest dose (300 Gy) were 29.1 ± 0.2 in air and 18.1 ± 0.3 in oxygen. In the ambient air + 270 Gy treatment egg hatch was 3.8 ± 0.1%, but in the oxygen + 270 Gy treatment it was 0%. When females were irradiated in air with 300 Gy, egg hatch was totally prevented. The number of F1 deutonymphs per P generation female irradiated with 270 Gy in ambient air was 4.0 ± 0.1, but the corresponding number that descended from females irradiated in pure oxygen was significantly reduced to zero. Percentage survival of females at 22 d post treatment was 13.0 ± 0.1 d when females were irradiated in oxygen with 270 Gy compared to 16 ± 0.2 d when irradiated in air with 300 Gy. Therefore, 300 Gy is recommended as an appropriate candidate for phytosanitary irradiation of B. yothersi in air, and 270 Gy is recommended as an appropriate candidate for phytosanitary irradiation of B. yothersi in oxygen.Artigo IPEN-doc 23528 Effect of gamma irradiation of gravid Tetranychus desertorum, T. urticae and Oligonychus ilicis (Trombidiformes: Tetranychidae) females on the viabilities and durations of F1 life stages2016 - MACHI, ANDRE R.; ARTHUR, VALTER; SARRIES, GABRIEL A.; PIEDADE, SONIA M. de S.The objective of the study was to evaluate—as an alternative phytosanitary treatment—the effects of gamma irradiation of gravid spider mite females on the viabilities and durations of F1 eggs and deutonymphs. The study focused on Tetranychus urticae Koch, Tetranychus desertorum Banks and Oligonychus ilicis (McGregor) (Trombidiformes: Tetranychidae). Each mite species was identified under a stereomicroscope, and individual female mites of each species were each taken with a fine-tipped brush and transferred to a Petri dish—i.e., 1 female mite individualized per dish with 32 dishes per species. Each dish with a Tetranychus spp. female was provided with a jack bean (Canavalia ensiformis [L.] DC) (Fabales: Fabaceae) leaf, and each dish with an O. ilicis female was provided with a coffee (Coffea arabica L.; Gentianales: Rubiaceae) leaf. Gravid female mites were irradiated in a Gammacell 220 cobalt-60 source—dose rate 0.486 kGy/h—with doses of 0 (control), 100, 200, 300, and 400 Gy with 32 replications per mite species. Evaluations were made every 24 h for 22 d after irradiation by counting the numbers of eggs, deutonymphs, and adults and by recording the mortality in each stage. Statistical analyses were done with generalized linear models with either the quasi-binomial distribution or the Gaussian distribution—as appropriate—for analyses of mortality rates and durations (d) of the F1 eggs and deutonymphs of the 3 mite species. A 3 × 5 factorial experimental design was used in which factor A (3 levels) pertained to the species and factor B (5 levels) pertained to the 4 radiation doses plus the control. For Factor B polynomial regressions of dose rates on biological effects were used. The results showed progressive decreases in egg and deutonymph viabilities that were proportional with progressive increases in radiation doses. Against O. ilicis 200 Gy prevented all F1 neonates from developing beyond the first instar. Against T. urticae and T. desertorum 300 Gy prevented all F1 neonates from developing beyond the first instar. Irradiation of gravid females caused the durations of the F1 egg stage and the F1 deutonymph stage to be prolonged.Artigo IPEN-doc 23951 Pupation, adult emergence, and F1 egg hatch after irradiation of Spodoptera frugiperda (Lepidoptera: Noctuidae) last instars2016 - ARTHUR, VALTER; ARTHUR, PAULA B.; MACHI, ANDRÉ R.The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a quarantine pest that may be found as eggs or larvae on a number of fresh vegetable and fruit commodities. The objective of the research was to evaluate the effects of gamma radiation as a phytosanitary treatment applied to the 5th (last) instar larvae. Larvae were reared on an artificial diet. Each treatment of twenty 15–20 d-old larvae had 5 repetitions. The larvae were irradiated with doses of gamma radiation of 0 (non-irradiated control), 50, 100, 200 and 300 Gy in a Cobalt-60 source (Gammacell-220) at a dose rate of 508 Gy/h. Pupation, adult emergence and hatching of F1 eggs were monitored. When the last instars were irradiated with100 Gy the rates of pupation, adult emergence and F1 egg hatch were 85, 39 and 50 percent, respectively, and the corresponding values in the non-irradiated control were 95, 85 and 90 percent, respectively. However, when the last instars were irradiated with 200 Gy, the pupation rate was reduced to 30 percent and adult emergence was reduced to 10 percent, and all of the adults that emerged were deformed, unable to fly, and died after about 2 h. Therefore, irradiation with 200 Gy is recommended as the appropriate dose for phytosanitary irradiation of S. frugiperda eggs and larvae. In addition this study supports the previously proposed generic dose of 250 Gy for eggs and larvae of lepidopteran pest species generally.Artigo IPEN-doc 23517 Development of phytosanitary irradiation against Aceria litchii (Trombidiformes: Eriophyidae) on lychee2016 - ARTHUR, VALTER; MACHI, ANDRE R.The lychee erinose mite, Aceria litchii (Keifer) (Trombidiformes: Eriophyidae), is the most important pest of lychee (Litchi chinensis Sonn. (Sapindales: Sapindaceae) in parts of China, India, Southeast Asia, South Africa and Brazil. This study sought to develop the basis for phytosanitary irradiation of lychee to provide quarantine security against this pest. New methodology had to be devised for this purpose because the adult, the largest life stage—about 200 μ long—cannot be seen without magnification, and because this species does not survive more than a few d even on detached young lychee leaves, or under other artificial conditions. Initially we adapted a method devised by Azevedo et al. (2013) for keeping the adults alive long enough to evaluate the lethal effects of candidate acaricides for at 48 h post treatment. We collected infested leaves from a lychee orchard and irradiated then with doses increasing by increments of 200 Gy in the range 0–2,000 Gy. Each infested leaf had 30 to 40 adult mites. Each of 3 replicates involved ~816 adult mites and ~2,450 adult mites per treatment. Because of the presence of predators hidden within the erinea, we collected 30 adult mites per replicate immediately after irradiation, and placed them in a 14-cm-diam petri dish with a new young lychee leaf and moist cotton. We covered each petri dish with parafilm® to prevent escape of mites and loss humidity. At 24, 36, and 48 h post irradiation, we counted the numbers of live and dead mites. At 24 h post irradiation mortality occurred only in 1,800 and 2,000 Gy treatments, and it was only 1.7% in both treatments. At 36 h mortality had increased to 11.1 and 24.4% in the 1,600 and 2,000 Gy treatments, respectively. At 48 h statistically significant mortality occurred with all doses in the 200–2,000 Gy range; and it was 73.3% and 100.0% in the 1,800 and 2,000 Gy treatments, respectively. Since 2,000 Gy is unacceptable for phytosanitary irradiation, a dose had to be identified that prevents reproduction, i.e., a F1 generation. To prolong the survival of irradiated mites for at least 13 d, which appears to be the generation time of Aceria spp., we cut infested fragments of leaf blades, examined the under a microscope to remove adults and immature forms of predators mites, placed them in petri dishes, irradiated them with doses increasing by increments of 100 Gy in the range 0–500 Gy, and glued each irradiated leaf fragment onto a newly flushed leaf of a potted lychee tree in a screened greenhouse. Each treatment had 4 replications, and each consisted of ~10 adult mites for a total of ~40 adult mites per treatment in the first trial and 18 adults per replicate for a total of ~72 mites in the second trial. By 72 h post irradiation the mortality rate was considerably greater with all doses in the range 200–500 Gy than at 48 h in the earlier experiment, and the percent mortality with 100 Gy was significantly greater than in the control (0 Gy). Therefore, 72 h post irradiation seems to be the minimum time required for the lethal symptoms of irradiation to develop within the dose-range that is relevant to phytosanitary irradiation of fresh plant materials. In both the first and the second trials, moderate symptoms of erinose developed during 18 d post irradiation in the treatments with 0–300 Gy, but no erinose symptoms developed in the 400 and 500 Gy treatments. All symptomatic leaves displayed the patchy growth of erinea, i.e., abnormal felt-like hairs on the abaxial leaf epidermis. In addition by d 18 some galls had been formed on the upper sides of some of the leaves with erinea. These data show that irradiation of A. litchii with ≥ 400 Gy prevented it from reproducing, which is a critically important criterion of phytosanitary irradiation. Additional experiments are needed in the 300–400 Gy range to find the minimum dose required for phytosanitary irradiation.Artigo IPEN-doc 23516 Adult emergence and F1 generation egg and larval production after γ-irradiation of late pupae of Grapholita molesta (Lepidoptera: Tortricidae)2016 - ARTHUR, VALTER; MACHI, ANDRE R.; ARTHUR, PAULA B.The late pupal stage (pharate adult) of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) close to adult emergence was irradiated with doses up to 350 Gy to determine a dose that could serve as a phytosanitary treatment against Lepidoptera that may pupate in shipped commodities. Adult emergence was not significantly reduced below that of the non-irradiated control until the dose reached 200 Gy. Not until the dose had been increased to 150 Gy was the number of eggs laid significantly less than the control, and oviposition was completely prevented at ≥ 300 Gy. Egg hatch was not significantly reduced compared with the non-irradiated control until the dose reached 150 Gy, and no eggs hatched at ≥ 250 Gy. This study supports a generic radiation dose for pupae of Lepidoptera of at least 250 Gy.