We propose a treatment strategy combining an initial disinfestation treatment with 1 of 3 protective treatments as an alternative for chemical fumigation of walnuts for control of postharvest insect populations. The initial disinfestation treatment (0.4% O-2 for 6 d)was designed to disinfest walnuts of held populations of navel orangeworm, Amyelois transitella (Walker). The protective treatments were low temperature (10 degrees C) storage, controlled atmosphere (5% O-2) storage, and application of the Indianmeal moth granulosis virus, and were designed to prevent establishment of Indianmeal moth, Plodia interpunctella (Hubner). The initial disinfestation treatment was effective against laboratory populations of navel orangeworm. Efficacy of protective treatments was determined by exposure to Indianmeal moth population levels far higher than those found in commercial walnut storage facilities. All 3 protective treatments prevented development of damaging Indianmeal moth populations as measured by pheromone trap catches and sample evaluation of the walnuts. No Indianmeal moths were trapped, nor were any seriously damaged walnuts (nuts with obvious damage that rendered the nutmeat less marketable or unmarketable) recovered from either low temperature or controlled atmosphere storage. Very low numbers of moths (less than or equal to 21/wk) were trapped from walnuts treated with virus, and only 0.2% of the walnuts were seriously damaged. In contrast, large numbers of moths (119-793/wk) were trapped from untreated nuts, and 35% of the sampled walnuts showed serious damage. Quality analysis by a commercial laboratory showed that overall walnut quality for all protective treatments was maintained at levels acceptable by industry standards.

High temperature alone and combined with controlled atmospheres were effective in killing diapausing codling moth larvae, Cydia pomonella (L.). Larvae were exposed to atmospheres of air, 0.5% oxygen (O2) in nitrogen (N2), 0.5% O2 + 10% carbon dioxide (C O2) in N2, or to 98% CO2 in air, at temperatures of 39, 41, 43, or 45 and 60% RH. LT95s were estimated for each atmosphere-temperature combination and fit to an asymptotic mathematical model to describe the effect of temperature. Higher temperature caused a more rapid kill. The decreasing order of effectiveness was 98% CO2, the two 0.5% O2 atmospheres, which were intermediate in effectiveness and not substantially different from each other, and air.

A prototype treatment chamber for application of high temperature alone or with controlled atmospheres was designed and tested for disinfesting walnut fruit of diapausing larvae of the codling moth, Cydia pomonella (L,.). All treatments were made at 43 degrees C with air, 0.5% oxygen (in nitrogen), or 98% carbon dioxide (balance air). Earlier in vitro laboratory research, at 43 degrees C, provided exposure time estimates for 95% mortality of 45.2 h for air, 14.6 h for 0.5% O-2, and 5.2 h for 98% CO2. Treatment of diapausing codling moth larvae within walnuts under these conditions in the prototype chamber resulted in mortalities of 97.6% for air, 96.1% for 0.5% O-2, and 97.6% for CO2. Surviving larvae were moribund and subsequently died.

Temperature and exposure times necessary to kill eggs of Fuller rose beetle, Asynonychus godmani Crotch, with hot-water immersion were determined and fitted to a mathematical model. The temperature rise beneath the calyx of lemons was also modeled during hot-water immersion. From these two models, a final model was developed to estimate the immersion time needed to kill eggs deposited beneath the calyx using 52-degrees-C water, and infested lemons were treated to validate the model. Egg mortality exceeded the predicted mortality. There were no survivors among 4,071 eggs infesting lemons when they were immersed for 8 min at 52-degrees-C.

Heat combined with controlled atmospheres increased mortality of Tribolium castaneum (Herbst) larvae when temperatures of ≥38°C were combined with carbon dioxide enriched or oxygen deficient atmospheres. Preconditioning of larvae to treatment temperature for 24 or 48 hr prior to controlled atmosphere treatments at 38°C significantly reduced larval mortality relative to a 1 hr preconditioning. Heat combined with controlled atmospheres can significantly reduce treatment time. However, if heat is applied prior to the application of controlled atmospheres, the time of treatment must be extended.

Eggs (0-3 d old) placed in open petri dishes or peroxide penetrable bags and last instar larvae placed in plastic bags were fumigated with vapor-phase hydrogen peroxide. Half of the bags contained 5 ‘Carmel’ almond nutmeats. The bags used for fumigation were constructed of Poly/Tyvek (American Sterilizer Co.) and were 8 cm wide by 13 cm long. Fumigations were conducted in a VHP Dental Sterilizer (fumitorium) manufactured by American Sterilizer Co., Apex, NC. One hundred eggs or ten larvae were placed per container and treated with a dose of 8.9 °9.0 g of 35% liquid H2O2 injected on either cycle I (deep vacuum 32mm Hg) or cycle II (shallow vacuum ca. 400mm Hg), both cycles employed repeated injections of 40 micro s duration over the treatment period. Preliminary testing indicated that cycle I produced greater mortalities than did treatment under cycle II, therefore, cycle I was employed for the reported tests. Each treatment required 30 minutes and chamber temperature rose to 43-47°C. Controls were treated as described except water was substituted for hydrogen peroxide. Each test was replicated three times.

Eggs weigh an average of 95mug and are 0.85mm in length by 0.46mm in diameter and are secured to the substrate with an adhesive that becomes relatively water insoluble 1 h after deposition. Egg development at 27-degrees-C was first observed on day two, having mitotic cells visible. on day three, the germ band migrates into the yolk and the germ band elongates then shortens during the next three days. By the seventh day, the cerebrum is visible and ganglia appear segmented by day eight. Longitudinal rotation of the embryo occurs on day nine and ten. Mandibles and eyes become visible on day twelve and thirteen with mandible sclerotization on day fifteen. Larval emergence starts on the seventeenth day.

The concentration of adenosine triphosphate (ATP) in relation to the viability of Fuller rose beetle, Asynonychus godmani Crotch, eggs was determined with the firefly, Photinus pyralis (L.), bioluminescent assay. ATP concentrations decreased significantly when eggs were killed by freezing, hot water, or methyl bromide fumigation. Two hours after eggs were frozen in liquid nitrogen, the ATP concentration was only 5% that of unfrozen, live eggs. The ATP concentration decreased logarithmically for the first 30 min after freezing; the ATP half-life was estimated to be 12.9 min. ATP concentrations in eggs killed by a 3-min dip in 55-degrees-C water dropped 40% 2 h after treatment. In eggs fumigated for 2 h with 80 g/m3 methyl bromide, the ATP concentration did not decrease for 8 h following treatment. However, after 24 h, ATP concentrations were 50% less than the nonfumigated eggs. The Fuller rose beetle eggs killed by all three treatments contained significantly less ATP than live eggs 24 h following treatment. Thus, the results suggest that the firefly bioluminescent ATP assay could serve as a rapid screening method for ascertaining Fuller rose beetle egg viability.

The mortality of 2-24 hr old Cydia pomonella (L.) eggs treated with oxygen (O2) deficient or carbon dioxide (CO2) enriched atmospheres is exposure time dependent. At 25-degrees-C and 95% r.h., O2 concentrations of 0, 0.5, 1, 2, and 5% (in nitrogen) produced LT95s of 1.2, 1.7, 1.6, 1.7, and 24.4 days, respectively. Pure nitrogen was significantly more effective than the other O2 deficient atmospheres. Carbon dioxide concentrations of 20, 40, 60, 80, and 100% (in air) produced LT95s of 3.6, 1.3, 1.4, 1.6, and 1.4 days, respectively. Only 20% CO2 induced significantly less mortality than the higher concentrations. Regression parameters for each atmosphere are given. Combining O2 deficient with CO2 enriched atmospheres did not increase C. pomonella egg mortality over that of the atmospheres used alone.Sublethal concentrations of CO2 enriched atmospheres altered C. pomonella reproductive capacity. Carbon dioxide concentrations of 40% or more reduced adult survival and reduced surviving adults ability to mate.

Ethyl formate, hydrogen cyanide, phosphine, and methyl bromide fumigants were tested for their efficacy for postharvest control of eggs of Fuller rose beetle, Asynonychus godmani Crotch, on lemons. Fuller rose beetle is a quarantine pest of citrus fruits entering Japan. Only methyl bromide use appears to be feasible for fumigating citrus fruits infested with beetle eggs. Fumigation of infested, unprocessed lemons at a 50% load factor for 2 h at 21-degrees-C with 44 g/m3 of methyl bromide resulted in a concentration x exposure time (CT) product of 75.6 g.h/m3, with mortality to eggs of 99.94%. Inorganic methyl bromide residue in lemon fruit pulp and peel averaged 5.0 and 12.2 ppm, respectively. Supplementing methyl bromide fumigation with 20% carbon dioxide did not improve insect mortality. Cold storage and shipping temperatures (normally used in handling citrus fruits destined for Japan) combined with methyl bromide fumigation also did not improve efficacy.

Since 1985 when eggs of the Fuller rose beetle, Pantomorus cervinus (Boheman), were found by Japanese fruit inspectors under the calyxes of California citrus, researchers have sought to develop alternatives to methyl bromide fumigation as a suitable quarantine treatment for this pest. Three different ages of Fuller rose beetle eggs laid on waxed paper were exposed to gamma radiation doses of 10, 50, 100, and 150 Gy. The oldest age class (10-13 d old) was the least susceptible. Egg hatch of the two younger age classes (1-3 and 6-8 d old) was prevented by 50 Gy, whereas 150 Gy was needed to prevent hatch of older eggs. To confirm the efficacy of the method, lemons infested with 10- to 13-d-old Fuller rose beetle eggs were placed in the center of standard cardboard lemon cartons and irradiated at doses averaging 174.1 Gy. Egg hatch from egg clusters infesting untreated lemons averaged (x ± SEM) 42.5% ± 4.66 per lemon. None of the estimated 6,500 eggs infesting irradiated lemons hatched. Damage of irradiated fruit varied but did not exceed a 6.1% increase compared with damage found in controls. These data show that irradiation of lemons could be an effective quarantine treatment against Fuller rose beetle eggs.

Eggs, mature larvae, diapausing larvae, pupae, and adult stages of codling moth, Cydia pomonella (L.), were exposed to two controlled atmospheres at 25°C and either 60 or 95% RH. The atmospheres used were either a simulated combustion atmosphere (0.5% O2, 10% CO2, balance nitrogen) such as that produced by an exothermic generator fueled with methane or propane, or a 60% CO2 in air atmosphere. Mortality data were converted to logits and multiple regression analyses of logit versus time were performed for each life stage. LT95's were estimated from the regression models. The trend from least to most tolerant stage was: eggs, adults < pupae < mature larvae < diapausing larvae. Atmospheres at 60% RH killed all life stages except eggs more quickly than those at 95% RH; for eggs, the difference was not significant. Except for pupae, the carbon dioxide atmospheres caused faster mortalities than the low oxygen atmospheres. LT95's for eggs were <2 d, while LT95's for larvae ranged from 7 to 19 d. Diapausing larvae were killed with 60% CO2 atmosphere in 13–24 d, whereas with the low oxygen atmosphere approximately 70% mortality was attained after 18 d at 60% RH, and 60% mortality was attained after 42 d at 95% RH.

Fuller rose beetle eggs (0-7 d old) oviposited between layers of wax paper, were placed in stainless steel cages (6 cm long by 18 mm diameter), immersed in test compounds, air dried for 30 min, and then held at 25°C and 85% RH for 30 DAT. To stimulate egg hatch, 24 h before mortality determination, the relative humidity was raised to saturation. For the Biphenyl test, eggs were placed in Petri dishes with Biphen-yl-impregnated papers of various sizes for 2 wk at 13°C, then held for 30 d as described above.

Eggs (0-7 days old) oviposited on wax paper were placed in stainless steel screen cages 6 cm long × 18 mm diam closed with cork stoppers. Cages with eggs were dipped in test compounds at recommended strengths for 3 min, drip dired for 1 min, rinsed in tap water for 1 min, and air dried for 30 min. The tap water rinse was omitted for Dimilin. Treated eggs were held at 27°C and 85% RH for 30 days and examined for mortality. There was an average of 387 eggs/replicate, and each test was replicated 3 times. All data were corrected using Abbott's formula (1925).

Populations of stored-product moths in raisin-marketing channels were evaluated with the pheromone (Z-E) 9–12 tetradecadien-l-ol acetate. Sticky traps baited with this pheromone attracted Indianmeal moth, Plodia interpunctella (Hübner); almond moth, Cadra cautella (Walker); raisin moth, Cadra figulilella (Gregson); Mediterranean flour moth, Anagasta kuehniella (Zeller); and tobacco moth, Ephestia elutella (Hübner). Indianmeal moth was found in very low numbers in a U.S. raisin-processing plant. Raisin moths were plentiful outside the plant, but were rarely found inside the plant. During transport of raisins to Rotterdam, The Netherlands, only almond moths were captured. Western European warehouses were infested with Indian meal moth, tobacco moth, Mediterranean flour moth, and almond moth. Only one raisin moth was trapped in these warehouses. Pheromone-baited traps are valuable for detection of insect infestation in marketing channels, and their use could lead to improved insect control programs and thus cleaner raisin products for the consumer.

Interaction of oxygen concentration, temperature, and relative humidity with time required to kill Indianmeal moth, Plodia interpunctella (Hübner) and navel orangeworm, Amyelois transitella (Walker), was examined. Late larval and early pupal stages of navel orangeworm and pupae of Indianmeal moth were exposed to combinations of 0.5, 1, 2, or 5% O2. (with 10% CO2 and a balance of N2) at 15.6, 21.1, or 26.7°C and at 40 or 60% RH. These gas concentrations simulate the output atmosphere of a low-O2 generator fueled with methane or propane. Lethal time to kill 95% (LT95) of the population of each insect was determined by regression analysis for each combination of factors. A general equation was developed through multiple regression analysis of the LT95's for each insect species to describe the relationships. Temperature effects were similar for each species and could be made linear with a reciprocal transformation of the LT95 plotted against time. Effects of relative humidity and atmosphere on the LT95 were different for the two species. Indianmeal moths were affected more by changes in O2 concentration while navel orangeworms responded more to changes in relative humidity. Further analyses led to estimates of the low temperature threshold (i.e., temperature below which atmospheres would be ineffective) and to estimates of a constant, k, describing the time/temperature relationship. The time/temperature curve is described by a hyperbola and exposure time can be estimated accordingly.

The sex pheromone of Harrisina brillians Barnes and McDunnough was bioassayed. Of four compounds from female tip dip extracts, only d,l-sec-butyl (Z)-7-tetradecenoate attracted male moths. Further testing showed that the d isomer was the attractant; when the l isomer was added to the d isomer, male attraction was reduced. Dose-response studies showed increased moth attraction with increased amounts of d,l-sec-butyl (Z)-7- tetradecenoate. A 100-μg dose of the d,l pheromone compared to the attraction of two virgin females resulted in an average daily male moth capture of 62% to the 100 μg dose and 38% to the two virgin females. Daily capture peaked at ca. 0845 hours (ca. 3 h into photophase [i.e., after sunrise]).

Stored raisins were successfully treated for control of Cadra figulilella (Gregson), Plodia interpunctella (Hübner), Drosophila melanogaster (Meigen), Carpophilus hemipterus (L.), Oryzaephilus mercator (Fauvel), O. surinamensis (L.), and Tribolium castaneum (Herbst) with a low-oxygen atmosphere. The atmosphere, consisting of ≤0.5% oxygen, 10 to 14% carbon dioxide, and a balance mainly of nitrogen, was produced by an exothermic generator that uses natural gas or propane fuel to “burn” oxygen out of the air. This atmosphere was introduced into commercial stacks (bulk storages) of raisins in a continuous-flow, single-pass operation; the atmosphere exiting the stack was not recirculated. Time for purging the raisin stacks to <0.5% O. was ≤48 h, and insect control was obtained in 5 days at 27°C and 14 days at 16°C.

The cost of low-oxygen atmosphere consisting of ≤0.5% O2/10–13% CO2 with the balance mainly N2 was compared with the cost of methyl bromide and phosphine for application to stored raisins for insect control. Methyl bromide was the most cost effective, at $8.39/metric ton, followed by low-oxygen atmosphere at $9.66 to $10.64/metric ton and phosphine at $10.76/metric ton. A low-oxygen atmosphere is cost competitive with phosphine for insect control in bulk-stored raisins.