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Subterranean termite control methods using chitin synthesis inhibitors (CSIs) aim at eliminating colonies that feed upon a bait formulation. Several benzoylurea active ingredient formulations are currently commercially available as alternative termite management strategies to liquid termiticides. Individual workers need to molt on a regular basis and CSIs interfere with such molting process, allowing sufficient time for the acquisition of a colony-wide lethal dose prior to widespread mortality. As workers progressively die, the colony eventually collapses, leaving only soldiers and primary reproductives that starve to death. One common observation is that young workers often die early owing to their relatively short molting cycle. However, the absence of brood in dying colonies raises questions about the potential fate of eggs laid by the queen. This study aims to determine if CSI baits also terminate the ability of a colony to produce a new cohort of workers by disabling the ongoing brood development. Incipient termite colonies were used to test the impact of noviflumuron on the queen's ability to lay eggs and on the eggs' ability to hatch. Our results showed that queens in colonies exposed to CSI not only initially laid less eggs than the control queens, but eggs also did not develop and were progressively cannibalized, eventually leading to colony establishment failure. This result implies that queens of mature colonies exposed to CSI would lose the ability to lay viable eggs as the colony collapses, leading to an absence of worker replacement, aiding in colony elimination. [ABSTRACT FROM AUTHOR]

Bed bugs (Cimex lectularius L.) are blood-feeding human ectoparasites. Their cryptic nature and pesticide resistance have led to an upsurge in infestation abundance and increased difficulty to achieve control. A dosage–response study was conducted for fumigation with sulfuryl fluoride against bed bug eggs at 25 and 15°C. The least accumulated dosage that resulted in 100% mortality was then used in a confirmation study in which adults, third-instar nymphs, and additional eggs were fumigated. It was determined that all life stages tested were killed after fumigations at 88.40 and 170.00 g-h/m3, at 25 and 15°C, respectively. These dosages correspond to an application rate of 1.7× (multiplier of the drywood termite rate of 1×). However, sulfuryl fluoride fumigations at 80.08 and 154.00 g-h/m3 (25 and 15°C, respectively) each yielded >99.6% mortality of bed bug eggs, the most fumigant-resistant life stage. These dosages, rounded to the closest tenth, correspond to an application rate of 1.5×. Thus, this study supports that the MasterFume label rate against bed bugs should be decreased from 3× to 1.7×, at the minimum, because fumigation at 1.5× would suffice due to overly conservative estimation of field factors when calculating fumigant dosage. [ABSTRACT FROM AUTHOR]

To determine whether volatiles from bed bug eggs were similar to the defensive secretions from nymphs and adults, headspace volatiles from eggs of the common bed bug (Cimex lectularius L.) were collected by aeration, daily until hatch, and subsequently analyzed by gas chromatography–mass spectrometry. We now report that eucalyptol (1,8-epoxy- p -menthane) was identified from all egg samples. Blank control samples containing no eggs had no evidence of eucalyptol. Positive controls, containing nymphs, adults, and fecal deposits, showed the presence of the defensive secretions (E)-2-hexenal and (E)-2-octenal, but no eucalyptol. The lack of detectable (E)-2-hexenal and (E)-2-octenal in viable egg samples and the detection of eucalyptol are discussed in relation to canine detection of bed bugs. [ABSTRACT FROM AUTHOR]

The mealybug of Dysmicoccus lepelleyi Betrem (Hemiptera: Pseudococcidae) attacks a wide range of fruits, vegetables, and ornamental plants and is categorized as a quarantine pest in China. Utilization of phytosanitary irradiation (PI) as a potential treatment to disinfest agricultural commodities in trade (which has expanded rapidly in the recent years) and preventing the hatch of F1 generation eggs is used as a criterion for the PI treatment of mealybugs. A RS-2000 Pro X-ray irradiator (Rad Source Technologies, Inc.) was used to treat the gravid adult females and eggs of the mealybug. The primary tests were conducted to explore the minimum dose for preventing egg-hatch from the irradiated adult females, resulted in a 1.69% of eggs hatched from 100 Gy-irradiated adult females and no crawler developed as treated at the dose of 110 and 120 Gy. To estimate the minimum dose for preventing egg-hatching, the dose–response tests were conducted for 1-, 2-, and 3-d-old eggs at the dose of 20, 40, 60, 80, 100, and 120 Gy, respectively. The results showed that the radio-tolerance increased very slowly with developmental times of eggs, and the estimated dose for 99.9968% mortality at the 95% confidence level (Probit 9) by Probit analysis is 146.2, 155.7, and 156.1 Gy for 1-, 2-, and 3-d-old eggs, respectively. Therefore, dose range between 110 and 160 Gy could be efficient to prevent the reproduction of this mealybug. [ABSTRACT FROM AUTHOR]

High-pressure processing (HPP) combined with heat or cold has been proposed as an alternative quarantine process for Mexican fruit fly Anastrepha ludens Loew (Diptera: Tephritidae). HPP conditions at levels higher than 100 MPa applied to destroy eggs and larvae can also affect the postharvest physiology of the fruits. HPP at pressure levels in the range of 50-100 MPa is recommended. Eggs have been reported as being more resistant to HPP than larvae. Therefore, the objective of this study was to assess the effect of a precooling treatment on the biological viability of A. ludens eggs treated by HPP at 0°C. The capability of nondestroyed eggs to develop and reproduce was also evaluated. One-, 2-, 3-, and 4-d-old eggs were precooled in ice water for 0 (control) 3, 6, 12, or 24 h and then pressurized at 50, 70, or 90 MPa for 0, 3, 6, or 9 min at 0°C. The hatching capability of pressurized eggs was evaluated. The most lethal effect of HPP on nonprecooled eggs (0 h) was obtained at 90 MPa for 9 min, destroying all eggs except for the 3-d-old ones, which showed an 11.8% hatch rate. Precooling treatment improved the hatch rate of eggs ranging from 4 to 50% depending on precooling conditions. The main effect was observed after 6 h. These results suggest that precooling modified the biochemistry and physiology of eggs, improving their resistance to HPP treatments. [ABSTRACT FROM AUTHOR]

The botanical insecticides, growth regulators, and pyrethroids have an effect on the biology of Spodoptera frugipercla (Smith). However, no emphasis has been given to the effect of these insecticides on embryonic development of insects, in histological level. Thus, this research aimed to examine by light and scanning electron microscopy S. frugiperda eggs and to describe the embryonic development, before and after immersion treatment, using commercial concentrations and lower concentrations than commercial ones, of the compounds lufenuron (Match), azadirachtin (AzaMax), and deltamethrin (Decis-positive control). For light microscopy semithin sections of eggs were used, and for scanning electron microscopy, images of the surface of eggs, treated and untreated with insecticides. The morphological characteristics of S. frugiperda eggs, in general, were similar to those described in the literature for most of the insects in the order Lepidoptera. Spherical eggs slightly flattened at the poles, with chorion, yolk, vitelline membrane, and embryo formation. In both microscopic analysis, we observed that insecticides acted immediately and independent of concen-tration, resulting absence, or incomplete embryo, presented yolk granules widely dispersed, without vitellophage formation, chorion disintegration, disorganized blastoderm, presenting vacuoles, yolk region with amorphous cells, and formation of completely uncharacterized appendages. Thus, we conclude that the compounds lufenuron and azadirachtin interfere on S. frugiperda embryonic development. [ABSTRACT FROM AUTHOR]