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The latania scale, Hemiberlesia lataniae (Signoret) (Hemiptera: Diaspididae) is a cosmopolitan and highly polyphagous species present on various hosts of economic importance. As with other scales, H. lataniae is quarantined by importing countries and a single viable insect can cause regulatory action. Ionizing irradiation is a promising phytosanitary treatment that is increasingly used worldwide. This study was conducted to determine a dose of radiation that would serve as a phytosanitary treatment for commodities at risk of carrying H. lataniae. Cobalt-60 gamma ray target doses of 50, 100, 150, and 200 Gy were used to irradiate immature and adult stages of H. lataniae infesting fruits of butternut squash, Cucurbita moschata Duschesne ex Lam (Cucurbitales: Curcubitaceae). Tolerance to irradiation in H. lataniae as measured by mortality was found to increase progressively as follows: first instars < second instars < adults. Adult females irradiated with a target dose of 200 Gy failed to produce offspring beyond the egg stage. Large scale tests involving a total of 31,877 female adults showed that a dose of 209 Gy (the highest dose measured when the target dose was 200 Gy) can serve as a phytosanitary treatment against H. lataniae. These results also support a generic dose of 250 Gy for all scale insects. [ABSTRACT FROM AUTHOR]

In Argentina the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is one of the 2 main whitefly pest species affecting several fruit and vegetable crops. Both adults and immature stages (nymphs) are presently feeding on many commercial crops, and a single live insect can cause regulatory actions by importing countries. Irradiation is a promising postharvest phytosanitary treatment that is steadily increasing in use worldwide. Cobalt-60 gamma-ray target doses of 30, 60, 90 and 120 Gy were used to determine the effect on irradiated eggs, 2nd instars and late pupae. The late pupa was the stage most tolerant to irradiation. Based on probit and logit analysis of the data obtained using at least 30,000 late pupae, the estimated doses to provide 99.9968% prevention of adult emergence from irradiated pupae were 170 and 222 Gy. Moreover, when late pupae (2 replicates totaling 33,625) were irradiated with a target dose of 100 Gy (maximum absorbed dose of 108 Gy) only 1,146 (3.4%) emerged as normal-looking adults, and they did not lay any eggs. Egg laying and hatch in the non-irradiated controls was normal. Therefore, 108 Gy should guarantee a secure phytosanitary treatment against T. vaporariorum. [ABSTRACT FROM AUTHOR]