Cautella Larvae Research Articles

Melanin pigmentation variations in the larval cuticle of almond moth, Ephestia cautella caused by gamma radiation

To determine the effects of gamma radiation on the melanization process and phenoloxidase activity, Ephestia cautella larvae were exposed to dosages of 200, 400, 600, 800, and 1000 Gy. After irradiation, the number of non melanized larvae and the number exhibiting a slight melanization usually increased. The degree of melanization in treated larvae differed significantly from untreated larvae. The amount of melanin usually decreases as the dosage increases and as time passes after the treatment. The results of the phenoloxidase assay indicate that the enzyme activity responds differently to radiation. For instance, at doses of 200, 400, and 800 Gy, the enzyme activity remained consistent in both control and irradiated larvae. However, at doses of 600 and 1000 Gy, the enzyme activity increased to 14.92 and 13.37 O.D. units, respectively, compared to 8.81 O.D. units in the control. In order to determine if irradiated larvae have been previously exposed to ionizing radiation, a quick and easy test based on phenoloxidase activity or the melanization response is presented for use in quarantine treatment. Histological changes, specifically in the pigment granules of melanin, were studied using a light microscope. Upon inspection of the unirradiated larvae, it was observed that brown melanin pigment granules were deposited in the epicuticle and exocuticle layers of the cuticle. When gamma radiation dosages were administered to larvae, it was observed that the melanin pigment gradually diminished until it vanished at the highest dose (1000 Gy).

Host preference and development of Habrobracon hebetor on larvae of Arenipses sabella and Ephestia cautella

ABSTRACT Habrobracon hebetor Say (Hymenoptera: Braconidae) is an larval ectoparasitoid, mainly of pyralid moths. The almond moth, Ephestia cautella Walker and the greater date moth, Arenipses sabella Hampson are two economic pyralid pests of date palm that were found to be attacked by the parasitoid. Although parasitised larvae of A. sabella are often encountered in the field, no data were available regarding their interaction with the parasitoid. The suitability of A. sabella as a host of H. hebetor was assumed, so it was tested and compared to that of E. cautella, which has received much research attention as an important host of the parasitoid. The parasitoid proved to be able to develop and reproduce on A. sabella larvae, and no significant difference was detected with E. cautella larvae. When the larvae of the two hosts were offered simultaneously to female parasitoids for 48 h, the rates of paralysis (0.98) and parasitism (0.93) were higher on E. cautella and consumed less time when checked every 12 h. This is likely because it is almost half the size of A. sabella. The larger size of A. sabella larvae supported the parasitoid to deposit more eggs on it. The nonsignificant difference in the results suggests that the parasitoid does not prefer one of the hosts over the other. The results of this study provide valuable insights into the effectiveness of H. hebetor against A. sabella for use in biological control strategies for controlling this pest after conducting more research in this promising area.

Ultra Violet (UV-B) radiation intrudes Cadra cautella reproductive biology by influencing vitellogenin expression

ObjectiveDate palm is a very important fruit crop growing in the world's warm climate. Several pests attack date fruit in the field and in storage. The almond moth, Cadra cautella, is a primary key pest which damages date fruits. Present research shows ultraviolet irradiation effect on mortality and reproduction of C. cautella female larval and female pupal stages in the laboratory. MethodsFemale larva aged 18 days and female pupae aged 1–2 days, were directly exposed to ultra violet (UV) type B in a chamber for 0, 2, 4, 6, and 12 h. Mortality of treated larvae and pupae was calculated and compared with the 0 h treatment (control). To quantify vitellogenin gene expression through real time polymerase chain reaction (RT-qPCR), larvae and pupae samples were collected from each treatment after each exposure interval and preserved at −80 °C. ResultsCadra cautella larvae and pupae, were vulnerable to the UV and the mortality was observed for all exposure intervals showing the highest mortality rate of 90 % larval mortality at 12 exposure interval. Whereas, in case of pupal mortality, 72.26 % mortality was observed after 12 h of exposure intervals. The UV-treated female pupae that survived the pupal developmental stage and emerged as adult moths were not healthy and were mostly deformed, preventing them from emerging from the puparium. Furthermore, when treated female moths emerged, they were unable to copulate with normal male moths, resulting in fewer unfertile eggs. In addition, the lethal effects of UV on vitellogenin gene expression in treated larvae and pupae were confirmed using real-time PCR, the results confirmed that UV had a harmful effect on vitellogenin gene expression. ConclusionsThe current study results are highly encouraging and may be useful in suppressing C. cautella populations in storages and managing this renowned pest of stored date fruits and other agricultural commodities on an industrial/commercial scale.

Efficacy of some entomopathogens against Ephestia cautella (Walker) (Lepidoptera: Pyralidae) in stored date fruits

BackgroundEphestia cautella (Walker) (Lepidoptera:Pyralidae) is one of the most economically important date fruits insect pests, which causes major losses in quantity and quality of the date yield. The present study aimed to evaluate 3 of the entomopathogens: Beauveria bassiana (Basonym 1836), Metarhizium anisopliae (Metchnikoff 1879), and Bacillus thuringiensis (Berliner 1915) var. kurstaki individually and mixed with each other against E. cautella in stored date fruits.ResultsFour concentrations from spores' suspension of each entomopathogen were sprayed on 50 eggs of E. cautella (24:48 h. old) (for fungal pathogens) and 30 2nd instar larvae of E cautella in glass jars. Pathogenicity was evaluated at different time intervals post treatments 3, 5,7and 14 days. Obtained results showed that mortality percentages of E cautella stages increased by increasing the tested entomopathogen concentrations and increasing of the exposure time. Results indicated that the reduction percentages of E. cautella eggs hatchability after separately treated at the concentrations (3.0 × 105, 3.0 × 106, 3.0 × 107 and 3.0 × 108 spores/ml) were (27.50, 39.17, 48.33 and 62.50%) for B. bassiana, (35.83, 44.17, 50.83 and 69.17%) for M. anisopliae, respectively. After14 days of treatment, the recorded larval mortalities were (49, 62, 77, and 81%) for B. bassiana and (60, 66, 78, and 89%) for M. anisopliae at concentrations (3.0 × 105, 3.0 × 106, 3.0 × 107and 3.0 × 108 spores/ml), respectively. In case of treating E. cautella larvae with B. thuringiensis, the mortality percentage was (44, 52, 63, and 72%) at concentrations (2.0 × 108, 2.0 × 109, 2.0 × 1010 and 2.0 × 1011 spores/ml), respectively, after14 days of exposure. E. cautella larvae were more susceptible to B. bassiana and M. anisopliae than the eggs. M. anisopliae was more effective than B. bassiana. The combination of the entomopathogens LC50 (B. bassiana + M. anisopliae, B. bassiana + B. thuringiensis, M. anisopliae + B. thuringiensis and B. bassiana + M. anisopliae + B. thuringiensis) caused E. cautella larval mortality percentages of 67.00, 73.33, 63.33 and 86.29%, respectively, 14 days after exposure. The combination of the 3 tested entomopathogens (B. bassiana + M. anisopliae + B. thuringiensis) increased their efficacy for controlling E. cautella.ConclusionsThe combination of the tested entomopathogens: B. bassiana, M. anisopliae and B. thuringiensis could be recommended for controlling E. cautella stages in stored date fruits.

The value of blue-green algae (Spirulina platensis) as a nutritive supplement and toxicant against almond moth [Cadra cautella (Lepidoptera: Pyralidae)

Blue-green algae, Spirulina platensis is a well-known algal formulation known for its beneficial effects on the growth and development in several types of organisms. Although it is used as a food supplement, it possesses significant toxic effects on growth and development of organisms. This study assessed the positive/negative impacts of S. platensis on almond moth, Cadra cautella (almond moth) that is a serious pest of date fruits and other grains under laboratory conditions. The S. platensis powder were mixed with diet and newly hatched C. cautella larvae were fed. The larvae were observed on alternate days to record the data. The diet was changed once a week. The S. platensis proved very good nutrition supplement at lower dose. Whereas, moderate and high mortality was noted for 5 and 10% formulations, respectively. Moreover, larval span was significantly altered by different formulations and lower formulation (1%) resulted in shorter larval period compared to the rest of the formulations. Although 33% mortality was recorded under 5% S. platensis formulation, however, the larvae which reached to adult stage, copulated, and females laid more eggs. Furthermore, the highest mortality (90%) was observed under 10% S. platensis formulation and a few larvae reached adult stage; thus, no data on pupal period and reproductive traits was recorded for this formulation. These findings proved that S. platensis can be used as nutritional supplement as well as a toxic substance to manage C. cautella in date storage. However, future studies on this are needed to reach concrete conclusions.

Effect of Pheromones, Plant Volatiles and Spinosad on Mating, Male Attraction and Burrowing of Cadra cautella (Walk.) (Lepidoptera: Pyralidae).

Simple SummarySex pheromones used at higher concentrations than their availability in insects have been successful in decreasing the insect population. Furthermore, botanical oils have also had negative impacts on the insect population level. In the first study, we investigated the combined effect of sex pheromones and plant oils on mating of almond moth. The second study sought the burrowing ability of almond moth larvae through different flour media. Mating declined on the presence of pheromones and botanical oils, whereas burrowing ability differed with flour type. Exposure to spinosad affected both mating success and larval penetration through flour media. The findings of this study reveal that various applications of sex pheromones, plant oils and spinosad ensure the better protection of cereal-based agricultural produce from insect infestation during storage.Mating disruption of Cadra cautella (Walk.) (Lepidoptera: Pyralidae) using its sex pheromone components, (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA), is successful in its population management. In addition, botanical oils have extensively been investigated in stored product pest management, but the effect of synthetic sex pheromones on the mating of C. cautella in the presence of plant volatiles is still unknown. Spinosad is used in food facilities as a contact insecticide but, if C. cautella larvae burrow into food, they may escape from spinosad. Importantly, the impact of spinosad on burrowing ability of C. cautella remains unknown. Therefore, the objectives of this study were to determine the effects of sex pheromone components ZETA and ZTA in the presence of botanical oils on the mating of C. cautella and the burrowing ability of C. cautella larvae in different types of flour treated with spinosad. In the first study, male and female moths were introduced into the cubicle having botanical oils and pheromone components. The mating status of female moths and male moth attraction to the trap was determined. The control experiments had only the botanical oils or pheromones. In the second study, burrowing ability of C. cautella larvae through different flour types was evaluated over 10 d. The flour was sprayed with spinosad (treatments) or water (controls). The mating success was higher with botanical oils alone but declined with exposure to pheromone either alone or combined with botanical oils. No differences in male attraction to traps were observed in botanical only, pheromone only or pheromone + botanical oil treatments. The burrowing of C. cautella larvae differed with flour type and spinosad altered burrowing ability. Thus, we conclude that the mating and burrowing of C. cautella is influenced by its pheromone and by exposure to botanicals and spinosad.

Effects of spinosad and spinetoram on larval mortality, adult emergence, progeny production and mating in Cadra cautella (Walk.) (Lepidoptera: Pyralidae)

The bacterial formulations, spinosad and spinetoram, were evaluated for their efficacy in suppressing development and mating success in Cadra cautella (Walk.) (Lepidoptera: Pyralidae), the almond moth. A dilution series of spinosad and spinetoram was sprayed on rice flour. Rice flour samples sprayed with water served as the control. Late instar C. cautella larvae were introduced onto spinosad-, spinetoram-, or water-treated rice flour. The first experiment tested the effects of spinosad and spinetoram on larval mortality, as well as emergence of adults and progeny at different insecticide concentrations. In the second experiment, the mating success of C. cautella adults that had emerged from larvae exposed to spinosad was tested inside a cubicle. Both spinosad and spinetoram increased larval mortality, whereas both compounds reduced adult emergence and progeny production. Natural mating was reduced in the presence of the synthetic sex pheromone (Z,E)-9,12-tetradecadienyl acetate. However, exposure of C. cautella larvae to spinosad did not alter mating in adult progeny. Spinosad was more effective than spinetoram at suppressing C. cautella development. The study concludes that both spinosad and spinetoram suppress the development of immatures of C. cautella to the adult stage as well as mating. Thus, the both compounds can be used to protect stored grains from infestation by C. cautella.

Aktivitas Repelensi dan Insektisidal Beberapa Ekstrak dan Minyak Nabati terhadap Hama Gudang Ephestia cautella

<p>Ephestia cautella<em> is one </em><em>type </em><em>of storage pest</em><em>s</em><em> that causes a decrease in cocoa bean</em><em> </em><em>quality. Control of th</em><em>is</em><em> pest using chemical insecticides is not recommended because it is harmful to the environment and consumer health. The research aimed to </em><em>examine</em><em> the repellency and insecticidal activity of several types of extract and botanical oil </em><em>against</em><em> </em>E. cautella<em> larvae. The </em><em>research was</em><em> conducted </em><em>in</em><em> the Plant Protection Laboratory, Indonesian Industrial and Beverage Crops Research Institute, </em><em>from </em><em>March to November 2012. </em><em>Botanical</em><em> materials used </em><em>were</em><em> water extracts from </em>Ageratum conyzoides<em> leaves, </em>Azadirachta indica<em> seeds, </em><em>and </em>Allium sativum<em> tubers, as well as oil from </em>Reutalis trisperma<em>, </em>Syzygium aromaticum<em>, and </em>Andropogon nardus<em>, </em><em>with respective</em><em> concentration of 0.5%. The insects test used was the 3rd instar larvae </em><em>generated</em><em> in the laboratory. </em><em>P</em><em>reliminary testing </em><em>of the </em><em>repellency activity was performed </em><em>used the</em><em> multiple</em><em>-</em><em>choice method, while subsequent testing used the dual</em><em>-</em><em>choice method with the parameter</em><em>s</em><em> of larvae </em><em>number remains i</em><em>n each treatment until 72 hours. The insecticidal activity was conducted using residual </em><em>method </em><em>on the feed substitute, by calculating mortality rate of the test insects. Observations were made at 24, 48, and 72 hours after treatment. The results showed that water extract </em><em>from</em><em> </em>A. sativum<em> bulbs and </em>A. conyzoides<em> leaves have high repellency percentage on the </em>E. cautella<em> larvae, i.e. </em><em>of </em><em>81.33% and 78.67%, respectively. Thus, the</em><em>se</em><em> two vegetable extracts have the potential to be </em><em>used as cocoa bean protectant </em><em>from </em><em>storage pest </em><em>attack</em><em>s.</em><em> The extract</em><em>s</em><em> </em><em>from</em><em> </em>A. indica<em> seed, </em>A. sativum<em> bulbs, as well as</em><em> oil from</em><em> </em>R. trisperma<em> and </em>S. aromaticum<em> showed insecticidal properties that are able to kill </em>E. cautella<em> larvae.</em><em></em></p>

Toxicity of Lantana camara Leaf Extracts Against Almond Moth, Cadra cautella (Walker)

The toxicity of various extracts of Lantana camara L. leaves was investigated against Cadra cautella (Walker) eggs, larvae and adults. For eggs and larvae film residue method and for adults specimen tube method was followed, then it was compared with azadirachtin technical (20 %). The toxicity of various extracts on egg, larval and adult mortality was compared. The egg mortality was based on their hatchability. It was observed that through film residue, most of the extracts of L. camara showed higher mortality as compared to azadirachtin. Based on LC50 values methanol fraction of hexane extract (LC-3) and hexane extract of hexane fraction (LC-4) of L. camara were found to be most effective against different stages of C. cautella. The mortality was dose dependent and it increased with increasing concentration. The leaf extracts of L. camara were positively toxic to insects. The effects of various extracts on different stages of C. cautella are discussed.

Efficacy of Bacillus thuringiensis (Berliner) isolates on fig moth, Ephestia cautella (Walker) Larvae

The following dilution 5×10-1, 10-1, 10?2 , 10-3 gm/L for the indigenous isolate of Bacillus thuringiensis bacteria and the commercially isalate were used for experiments against the different stages of fig moth of E.cautella which exposed by filter paper method. The results showed that mortality of larval stages was increased with the increasing concentration of the biocide, in addition to increase in the mortality of the larval stages reached to the highest percentage in the third days of treatment of the larval stage in comparison with the first and second days of exposure. The results also showed that the sensitivity of larval stages was increased in first and second instars while reduced in the last instars .The high percentage of first instar mortality for the indigenous isolate in the concentration of 5×10-1 was 72.8% , while the low percentage of mortality showed in the concentration of 5×10-1 for the fifth instar larvae which was 13.3% in third days of treatment while a high percentage of mortality was showed for the first instar larvae for the commercially isulate in the concentration of 5×10-1 was 59.4% Furthermore, low percentage of mortality was shown in the concentration of 5×10-1 in fifth instar larval which was 8.3% in the third days of treatment. The results also showed that the indigenous isolated was more effective than the commercially produced bacteria for killing larval instars of fig moth E.cautella .The total percentage of larval instar mortality reached to 44.5 % after the third days of treatment in concentration 5×10-1 in the indigenous isolate , and it was 33.8 % in the commercially produced bacteria .

Efficacy of Bacillus thuringiensis (Berliner) isolates on fig moth, Ephestia cautella (Walker) Larvae

The following dilution 5×10-1, 10-1, 10?2 , 10-3 gm/L for the indigenous isolate of Bacillus thuringiensis bacteria and the commercially isalate were used for experiments against the different stages of fig moth of E.cautella which exposed by filter paper method. The results showed that mortality of larval stages was increased with the increasing concentration of the biocide, in addition to increase in the mortality of the larval stages reached to the highest percentage in the third days of treatment of the larval stage in comparison with the first and second days of exposure. The results also showed that the sensitivity of larval stages was increased in first and second instars while reduced in the last instars .The high percentage of first instar mortality for the indigenous isolate in the concentration of 5×10-1 was 72.8% , while the low percentage of mortality showed in the concentration of 5×10-1 for the fifth instar larvae which was 13.3% in third days of treatment while a high percentage of mortality was showed for the first instar larvae for the commercially isulate in the concentration of 5×10-1 was 59.4% Furthermore, low percentage of mortality was shown in the concentration of 5×10-1 in fifth instar larval which was 8.3% in the third days of treatment. The results also showed that the indigenous isolated was more effective than the commercially produced bacteria for killing larval instars of fig moth E.cautella .The total percentage of larval instar mortality reached to 44.5 % after the third days of treatment in concentration 5×10-1 in the indigenous isolate , and it was 33.8 % in the commercially produced bacteria .

Influence of Chlorpyrifos-methyl on the Biochemistry of Haemo-lymph and Fat Body of the Larva of Almond Moth, Ephestia cau-tella Walker (Lepidoptera: Pyralidae)

The almond moth, Ephestia cautella Walker larvae cause serious damage to wheat, maize, peanuts, pulse, cocoa beans, dried fruits etc. The haemolymph and fat body play major roles in the insect developmental physiology. Proteins and amino acids are important biochemical constituents of haemolymph and fat body of the insects. Changes in the total protein and total free amino acids level were studied in the haemolymph and fat body of third instar larvae of almond moth exposed to sublethal concentrations of chlorpyrifos-methyl. The sublethal concentrations i.e. 1, 2 and 4 ppm of chlorpyrifos-methyl caused a significantly dose-dependent reduction in the level of total protein and an associated enhancement in the total free amino acids level in haemolymph and fat body tissue of the E. cautella larvae. The maximum decrease in total protein level in haemolymph (37% of the control value) and fat body (46% of the control value) was observed in larvae treated with 4 ppm of chlorpyri- fos-methyl. The maximum enhancement in the total free amino acids level in haemolymph (175% of the control value) and fat body (172% of the control value) was observed in larvae treated with 4 ppm of chlorpyrifos-methyl. The imbalances of bio- chemical constituents resulted abnormalities in developmental physiology such as retention of old cuticle, lethargy, lose of body fluids and death.

Effect of gamma irradiation on food consumption, assimilation and digestive enzymes in Ephestia cautella (Walker) larvae

The effects of gamma irradiation on the consumption, digestion and utilization of food by 8-18-day-old larvae of Ephestia cautella treated as 1-day-old larvae with 80 Gy, and also on the activity of protease, amylase and invertase enzymes, were studied. Gamma irradiation decreased the amount of food consumed and digested by the treated larvae in comparison with un-irradiated ones. It also reduced assimilation efficiency which further reduced weight gain. Protease, amylase and invertase enzyme activity was adversely affected in all irradiated larvae. The results revealed a positive correlation between the activity of the digestive enzymes and the amount of food digested by the larvae.

Regulation of Wolbachia density in the Mediterranean flour moth, Ephestia kuehniella, and the almond moth, Cadra cautella.

The Mediterranean flour moth, Ephestia kuehniella, is infected with A-group Wolbachia (wKue), and the almond moth, Cadra cautella, is doubly infected with A- and B-group Wolbachia, which are designated as wCauA and wCauB, respectively. In both insects, the Wolbachia populations increased greatly during embryonic and larval stages. The Wolbachia population doubled every 3.6 days on average in E. kuehniella larvae, whereas those of wCauA and wCauB doubled every 2.1 days in C. cautella larvae. The populations of wCauA and wCauB that had been transferred into the E. kuehniella background increased at similar rates to that of wKue in the natural host E. kuehniella, suggesting that the host genetic background influences Wolbachia proliferation. To examine whether the populations of the two Wolbachia variants in double infection is regulated collectively or independently, we measured the infection load in the ovaries of three transfected E. kuehniella lines in different infection states: single infection with wCauA, single infection with wCauB, and double infection. The density of each Wolbachia variant did not differ significantly between the singly and doubly transfected hosts, suggesting independent regulation.

Vacuumized and Unvacuumized Polyethylene or Polyester Film Bags: Insect Survival and Resistance to Insect Penetration1

Insect survival and reproduction were determined in vacuumized (V) and unvacuumized (UV) polyethylene (PE) or polyester (PET) bags of shelled peanuts. Tribolium castaneum (Herbst) larvae and adults survived and reproduced in V-PE (200 millibars) bags, and larvae survived, developed to adults, and reproduced in UV-PE bags. At 12 mo, live insects were found in UV-PE bags artificially infested with larvae and in V-PE bags initially infested with adults. Lasioderma serricorne (F.) and T. castaneum larvae matured to adults in V-PET and UV-PET bags, but no reproduction occurred when these bags were artificially infested with either adults or larvae. L. serrlcome adults reproduced in UV-PE as well as in V-PE bags. Cadra cautella (Walker) larvae matured and reproduced in UV-PE bags and matured in V-PE bags. C. cautella and L. serricorne penetrated the PE film. None of the three species tested reproduced in PET bags or penetrated these bags. PET bags exposed to external infestations were not penetrated. All V-PE bags were penetrated, whereas only 10% of the UV-PE bags were penetrated. The remaining intact bags developed low internal pressures during 12 mo of storage.

Effects of three temperature regimes on rearing and biological activities of Bracon hebetor (Say) (Hymenoptera: Braconidae)

The body color of Bracon hebetor adults was either black, yellow with black spots, or completely yellow when development from egg to adult took place at 15–18°C, 25 or 35°C, respectively, and the wasps were reared on Ephestia cautella larvae. The longest adult life-span of both sexes occurred when adults reared and emerged at 25°C were held at 15–18°C. Female adults of all colors lived longer than males, especially at 25 and 35°C. The lowest parasitizing efficiency was at 35°C, whereas the highest number of eggs per female occurred at 25°C irrespective of the body color. In general, the parasitoid wasps have somewhat tolerated the three temperature levels and continued to reproduce in spite of their distinct variations in body color. Such variations might be of importance as a mechanism of survival for B. hebetor in date stores during the cold season as well as in the green date palm and cotton fields during warm seasons in Iraq.

Effects of Larval Age on the Susceptibility of Almond Moths and Indianmeal Moths to Bacillus thuringiensis12

Larvae of the almond moth, Ephestia cautella (Walker), were highly susceptible to Bacillus thuringiensis Berliner in their diet if exposure began during the 1st stadium; they were less susceptible if exposure began dunng the later stadia. Larvae of the Indianmeal moth, Plodia interpunctella (Hübner), also were highly susceptible if exposure began during the 1st or 2nd stadium, but only the last (4th) stadium showed low susceptibility. B. thuringiensis caused a large increase in the development time of E. cautella larvae but caused little increase in that of P. interpunctella. The bacterium had no discernible effect on the sex ratio or reproductive capacity of moths that developed from surviving larvae.

Host Utilization by Bracon hebetor 1

When Ephestia cautella (Walker) larvae that have been paralyzed by Bracon hebetor Say are aged, the number of hosts remaining moist and thus suitable to the parasites for adult feeding, oviposition and offspring development declines by 15%/wk. Hemolymph ingestion from aged paralyzed hosts equals that from freshly paralyzed hosts. Parasites given a choice between aged and freshly paralyzed hosts consistently lay 68.7% of their eggs on the fresh. The number of parasites developing on aged paralyzed hosts is 0–25% lower than the number developing on freshly paralyzed hosts. The prolonged suitability of the parasite-paralyzed host means that B. hebetor has considerable time to relocate the hosts that crawl away after envenomization, but before paralysis is complete. Thus, the rates of accumulation and utilization of these hosts are a significant part of the natural dynamics of parasite populations and may be manipulated for pest management.

The effects of a previous field infestation upon Ephestia cautella (Walker) and Lasioderma serricorne (F.) infesting carobs

In laboratory trials, larvae of Ephestia cautella (Walker) successfully developed upon sections of the pods of the carob tree ( Ceratonia siliqua L.) which had previously been infested in the field by Ectomyelois ceratoniae (Zeller), but failed almost completely to develop upon sections of the pods which had not been infested in the field. Significantly more eggs were laid by Ephestia cautella adults on previously infested carob than on previously uninfested carob, and when newly-hatched Ephestia cautella larvae were given a choice between previously infested carob and previously uninfested carob, significantly more of them selected the previously infested carob. Larvae of Lasioderma serricorne (F.) developed successfully on both previously infested carob and previously uninfested carob, and neither adult nor larval Lasioderma serricorne could be shown to discriminate between previously infested and undamaged carob.

Pathogenicity of a nuclear polyhedrosis virus of the almond moth, Cadra cautella

Tests were conducted with neonate Cadra cautella larvae to determine the pathogenicity of a nuclear polyhedrosis virus. A bioassay on an agar base diet showed that concentrations of 0.25, 0.50, 2.00, and 4.00 polyhedra/mm 2 killed 27, 55, 87, and 92% of the test larvae, respectively. A study of the time of death showed that most larvae died on the 9th or 10th day after exposure to 4 polyhedra/mm 2 at 27°C. When larvae were exposed to 8, 16, 32, and 64 × 10 3 polyhedra/g of bran diet, recorded mortalities were 18, 22, 48, and 80%, respectively. All the samples of virus in bran diet which were incubated at various temperatures for 7, 14, and 28 days remained stable at all test conditions except the sample incubated at 42°C for 14 days, and those held at 37° and 42° for 28 days. Larvae of C. cautella, Plodia interpunctella, Ephestia elutella, and Paramyelois transitella placed on a diet with 40 × 10 3 polyhedra/g had mortalities of 75, 59, 16, and 4%, respectively. Light and electron microscopical examination of P. interpunctella cadavers showed that they were infected with a multiply occluded nuclear polyhedrosis virus.