Rhizopertha Dominica Research Articles

Glucosinolate aglucones and analogues: insecticidal properties and a QSAR

Naturally occurring aglucones of three glucosinolates (sinigrin, glucotropaeolin, and epi-progoitrin) were tested for fumigation activity against the house fly, Musca domestica, and the lesser grain borer, Rhizopertha dominica. A total of eight natural aglucones were evaluated in the bioassays. Two aglucones of sinigrin showed efficacy against both species which was comparable with that of a commercial fumigant, chloropicrin. None of the aglucones tested was comparable in activity to dichlorvos. Aglucones of glucotropaeolin were also insecticidal, but not to the same level as the sinigrin aglucones. The aglucones of epi-progoitrin were only slightly effective as fumigants. A quantitative structure–activity relationship (QSAR) was developed for synthetic analogues of the sinigrin and glucotropaeolin aglucones. An electronic parameter, σ*, provided the best predictor of activity in R. dominica, whereas a hydrophobicity parameter, π, best predicted activity in M. domestica. © 1998 Society of Chemical Industry

Characterization of malathion resistance in a Mexican population ofRhizopertha dominica

Malathion resistance of a field-collected population of Rhizopertha dominica (Coleoptera: Bostrichidae) from Mexico was evaluated and the resistance mechanisms were characterized both in vivo and in vitro. The Mexican population showed a resistance level of 50-fold at LC50 as compared with that of a susceptible laboratory population. Malathion bioassays with the synergists triphenyl phosphate, piperonyl butoxide and diethyl maleate suggested that esterases were likely to contribute to the resistance whereas cytochrome P450 monooxygenases and glutathione S-transferases were not. In-vitro assays of esterases indicated that the general esterase activity was 1·3-fold higher in the Mexican population than in the susceptible population. However, the phosphotriesterase activity in the resistant population was 3·7-fold higher than in the susceptible population. Significantly higher phosphotriesterase activity in the resistant population was further indicated by 3·4-fold increase of Vmax in enzyme kinetics and higher frequency of individuals with high phosphotriesterase activity in this population. All these findings suggested that phosphotriesterases play a role in malathion resistance in the Mexican population of lesser grain borer. © 1998 SCI

Polyphenol and Phytic Acid Contents of Cereal Grains As Affected by Insect Infestation

Polyphenol and phytic acid contents of wheat, maize and sorghum varied significantly and increased progressively with the levels of grain infestation (25, 50 and 75%) caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius separately and mixed population. Higher insect infestation (50 and 75%) of wheat and sorghum led to substantial increase (by weight) in polyphenol and phytic acid due to the selective feeding activities of the beetles. Feeding of both insect species on maize caused proportional increase in polyphenol but decrease in phytic acid due to variation in the distribution of these compounds in seed components and also selective feeding habit of insects. Storage of uninfested cereal grains for up to 4 months did not cause appreciable change in the levels of these antinutrients

Efficacy of some plant products as grain protectants againstRhizopertha dominica(F.) (Coleoptera; Bostrichidae)

Abstract Twenty‐two medicinal plant powders, ash of plant origin and sorbic acid were evaluated as grain protectants against Rhizopertha dominica (F.). Rauwolfia serpentina sorbic acid, Acorus calamus, Messua ferrea and Alblzia lebbeck were found effective at 1 % (w/w) in a first screening test and all these products were further assessed at 0.25, 0.5 and 1.0% (w/w). Rauwolfia serpentina completely inhibited feeding and F1 progeny production whereas sorbic acid inhibited infestation by more than 85% and F1 progeny production by 93% even at a concentration of 0.25%. Messua ferrea and A. calamus achieved more than 80% suppression at 0.50%. Albizia lebbeck exerted appreciable control at 1%.

Effect of insect infestation on the organoleptic characteristics of stored cereals

Two major pests of stored cereals in tropical and subtropical regions of Asia and Africa, Rhizopertha dominica Fabricius and Trogoderma granarium Everts, were used in experiments to investigate the effect of insect infestation on organoleptic characteristics of stored cereals. Infestations were achieved by releasing the two insect species either singly or in mixed populations in samples of wheat, maize and sorghum. These releases resulted in infestation levels of 25, 50 and 75%. ‘Chapatis’ made from infested and uninfested grain flours were evaluated for colour, taste, texture, aroma and appearance by a panel of semi-trained judges. There were no significant differences in the scores for colour, appearance, aroma and texture at all infestation levels for all three cereal grains and the scores also did not differ significantly from uninfested grains. However, at 50 and 75% infestation levels, scores for the taste of chapatis of three cereal grains were significantly ( P < 0.05) lower than uninfested grains. Bitter taste also resulted in poor overall acceptability of chapatis prepared from flours infested at the 50 and 75% levels.

A survey of storage coleoptera which attack dried cocoyam chips in Nigeria

In a survey of five locations in Anambra State, Nigeria, 13 species from 11 families of the Coleoptera were recorded from dried cocoyam chips. These include primary grain pests such as Araecerus fasciculatus, Dinoderus procellus, Rhizopertha dominica, Sitophilus zeamais and Tenebroides mauritanicus, bran and flour beetles like Brachypelus pilosellus, Tribolium castaneum and Tribolium confusum, and two other species namely Dermestes maculatus and Necrobia rufipes commonly associated with dried fish and meat. This array suggests severe cross infestation which normally results from poor storage and transportation conditions, and portends serious problems for future processing and storage of this product. Cocoyam chips were similar as a food material to other root crops, e.g. yam and cassava, for the development of A. fasciculatus, Dinoderus porcellus, S. zeamais and Tribolium castaneum but were not as good as cowpea or maize. With increasing interest in dried cocoyam products, especially in their use as starch fillers in the manufacture of biodegradable polyethylene materials, the economic significance of insect damage should be given more attention.

Available carbohydrates of cereal grains as affected by storage and insect infestation

Total soluble sugar, reducing sugar, non-reducing sugar and starch contents of wheat, maize and sorghum grains were affected adversely at 25, 50 and 75% insect infestation caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius, separately and mixed population. R. dominica caused significant (P < 0.05) reduction in available carbohydrates at 50 and 75% infestation levels whereas T. granarium achieved similar effect at 75%. Mixture of both insect species caused intermediate losses. Storage of cereal grains up to 4 months resulted in substantial increase in sugars and decrease in starch content, but storage for a shorter period of time did not cause any significant changes in levels of carbohydrates.

Protein and uric acid contents of cereal grains as affected by insect infestation

A significant increase was recorded in the levels of total nitrogen, total protein, non-protein nitrogen and uric acid contents of wheat, maize and sorghum grains having 25, 50 and 75% infestation caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius separately and in mixed population. On the other hand, there was a significant reduction in protein nitrogen and true protein contents of three cereal grains at 75% infestation level but the decrease was non-significant at the 25 and 50% levels of grain infestation as compared to control (uninfested grains). Both insect species produced uric acid contents above acceptable limits (10 mg/100 g) even at 50% infestation levels in three cereal grains. Variations in contents of nitrogenous compounds during storage (1, 2 and 4 months) were marginal.

Activity of a juvenile hormone analogue as a protectant against the lesser grain borer, Rhizopertha dominica (F.) (Coleoptera: Bostrichidae)

The juvenile hormone analogue (JHA) 6’, 7’,-epoxy-3, 7’-dimethyl-undec-2’-enyl 6-ethyl-3-pyridyl ether at 10 ppm (v/v) applied to whole wheat grains was not toxic to adult insects, but effectively reduced the F, generation of the lesser grain borer, Rhizopertha dominica (F.). However, topical applications of 4 ppm (v/v) of the JHA prevented normal metamorphosis of the larvae and pupae; all the test insects died due to morphogenetic abnormalities induced by treatment with the JHA.

Oogenesis in the lesser grain borer, Rhizopertha dominica(Fabricius) (Coleoptera : Bostrichidae)

The morphology and ultrastructure of ovarioles in Rhizopertha dominica (Coleoptera : Bostrichidae) are described. Ovarioles are of telotrophic type and are composed of an apical terminal filament, trophic chamber, and vitellarium. The trophic chamber consists of numerous individual trophocytes that remain connected by intercellular bridges. The vitellarium is composed of 3 oocytes, 2 of them are in the previtellogenic young phase, the 3rd (terminal one) is in the vitellogenic or chorionic phase. Individual oocytes are joined with trophocytes by long trophic cords. Special attention is paid to the morphogenesis of follicular cells and oocyte nucleus (germinal vesicle).

Effect of storage and insect infestation on protein and starch digestibility of cereal grains

Protein and starch digestibility of wheat, maize and sorghum grains increased marginally during storage, except for starch digestibility of sorghum which increased significantly ( P<0.05) after 4 months of storage. Protein and starch digestibility of three cereal grains having 25, 50 and 75% grain infestation caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius separately and in mixed form were affected significantly ( P<0.05) and adversely. T. granarium, primarily a germ feeder, reduced protein digestibility of wheat and maize more than did R. dominica or a mixed population of both insect species. By contrast, R. dominica, an endosperm feeder, reduced starch digestibility of three cereal grains compared with T. granarium and a mixed population. The reduction in digestibility was dependent on the distribution of proteins and starch in seed components as well as feeding preferences of insects.

Stored grain insects in underground storage pits in Somalia and their control

Seven species of stored grain pests were found infesting underground storage pits “bakars” tn the Bay Region of Somalia. These species and their relative abundance (%) in “bakars” are as follows: Alphitobius laevigatas (Fabricius) (Coleoptera, Tenebrionidae) (3.7%), Palorus subdepressus (Wollaston) (6.1%), Tribolium castaneum (Herbst) (29.2%); Rhizopertha dominica (Fabricius) (Bostrichidae) (23.9%); Sitophilus oryzae (Linneaeus) (Curculionidae) (4.7%); Cryptolestes ferrugineus (Stephens) (Cucujidae) (32.4%); Sitotroga cerealella Oliver (Lepidoptera, Gelechiidae) (unsampled). The mean percentage damage by insects for the region was 10.4 and by rats was 8.4 for sorghum grain stored as heads in 100 “bakars”. Actellic, K-Othrine and Malathion, applied as a 2% dust to threshed durra sorghum grain stored in sacks above ground, provided 99.2, 99.5 and 94.5% control, respectively.

Insect pests, Aspergillus flavus and aflatoxin contamination in stored wheat: A survey at North Bihar (India)

Fifty stored wheat samples (25 each of insect pest free and infested) were collected from North Bihar (India). Of the four major pests recorded, Sitophilus oryzae was the dominant insect, followed by Tribolium castaneum, Rhizopertha dominica and Trogoderma granarium. Aspergillus flavus was recorded in all samples: infection in insect-damaged samples was 87% and in insect-free samples 25%. Aflatoxin contamination was found in 19 and 2 of the insect-damaged and insect-free lots respectively. The role of insect pests in making wheat grains vulnerable to A. flavus infection and subsequent aflatoxin production is discussed.

Insecticidal activity of some penta‐ and hexa‐coordinated heterocyclic β‐diketone derivatives of diorganotin(IV) against the stored product pest Rhizopertha (Coleoptera: Bostrichidae)

AbstractSome new penta‐and hexa‐coordinated diorganotin complexes of heterocyclic β‐diketones having the general formula (n‐C4H9)2Sn(OPr1)2−n[RCOC:CON(C6H5) N:CCH3]n (where RCH3, C6H5 and p‐ClC6H4 and n = 1 and 2) have been synthesized and were screened for their insecticidal activity against Rhizopertha dominica (Fabricius), the lesser grain borer. The hexa‐coordinated complexes have been observed to be more active than the penta‐coordinated complexes.

Synthetic Juvenile Hormone Analogues Against Four Species of Stored Products Beetles

Juvenile hormone analogues (JHAs), JHA I (6,7’-epoxy3,7’-dimethyl-dec-2’-enyl 6-ethyl-3-pyridyl ether), JHA II (3’,7’-dimethyl-undec-2,6’-dienyl 6-ethyl-3-pyridyl ether), MV-678 (2-methoxy-9-[4-isopropyl phenyl]-2, 6-dimethylnonane), and R-20458 (4-ethylphenyl-6, 7’-epoxy-geranyl ether) in acetone solution were applied to insect diets at 10 ppm (v/v), and their effects on four species of stored products beetles observed. The larvae of the flour beetles, Tribolium confusum Jacquelin du Val, and Tribolium castaneum (Herbst), reared in media treated with JHAs I and II failed to pupate. At the end of the 6-week observation period, these larvae had not yet pupated. MV-678 and R-20458 produced ecdysial failures, lethal morphological abnormalities and larval/pupal and pupal/adult intermediates. Only a few apparently normal adult flour beetles emerged from these treatments. The lesser borer grain beetle, Rhizopertha dominica (Fabricus), completely failed to reproduce in a medium treated with JHA I. JHA II, MV-678 and R-20458 affected the reproduction of the two grain beetles, R. dominica and Sitophilus oryzae (L.), to varying extent, with MV-678 being the least potent JHA.

Current status of conventional insecticides in stored product insect management in India

DDT and BHC were used prior to 1954 as grain protectant but gradually malathion was adopted as prophylactic spray at 50 mg/m2. However, during the continuous usage, doses were enhanced up to 150 mg/m2 to meet the level of effective kill. Toxicity studies on different surfaces, seeds, moisture content level, different insects and stages and emergence of resistance were carried out with respect to malathion and several newer insecticides. DDVP was incorporated in spray schedule at 100 mg/m2. Toxicity data on 17 insecticides, three formulations, persistence on six surfaces and three seeds, tests on 13 insects have been utilized to evolve a strategy for future developments of a prophylactic insecticides. Demerits of switching to new insecticides without broad-based toxicity data have also been advocated. Insects, such as, larva of Trogoderma granarium Everts and adults of Tribolium castaneum (Hbst.), Rhizopertha dominica Fab., Callosobruchus maculatus Fab., Lasioderma serricorne Fab. and Sitophilus oryzae Linn, among beetles and Ephestia cautella (Wlk.) and Corcyra cephalonica Staint from moths were found least susceptible to most of the insecticides. Etrimfos and deltamethrin were adjudged superior for large scale use specially as wettable powder and adjudged suitable to sub-tropical conditions. The paper also provides information on currently used insecticides in India, methods of grain storage at rural and organized level and various constraints faced in the developing countries.

日本から初めて発見されたナガキクイムシ科２種

Recently, the writer examined the specimens of Dinoderus befoueolatus (WOLLASTON) from imported rattan desk and chair in Tokyo and Heterobostrychus aequalis (WATERHOUSE) from seasoned wood of imported lauan timber in Naha, Okinawa. These two tropical bostrychid beetles are firstly founded in Japan. Now, Japanese bostrychid fauna consists of the following 16 species, belonging to 9 genera : Eudecatomus lanatus LESNE, Rhizopertha dominica (FABRICIUS), Dinoderus minutus (FABRICIUS), D. bifoveolatus (WOLLASTON), D. japonica LESNE, D. speculifer LESNE, Sinoxylon japonicum LESNE, Lichenophanes carinipennis (LEWIS), Heterobostrychus aequalis (WATERHOUSE), H. hamatipennis (LESNE), Bostrychopsis affinis LESNE, Xylothrips flavipes (ILLIGER), Xylopsocus bicuspis LESNE, X.capucinus (FABRICIUS), X. castanopterus (FABRICIUS), and X. galloisi LESNE. A number of exotic species, intercepted from time to time in imports from tropical countries are not mentioned in above species. Amony them, serious pests are Dinoderus minutus injurious to dried bamboo and Rhizopertha dominica to all kinds of stored grains. Sometimes Dinoderus japonicus damage to bamboo at the local level.The biological notes and distinguishable characters of each species of genera Dinoderus and Heterobostrychus from Japan were given in this paper. New discovered species, Dinoderus befoueolatus may be distinguished from other Japanese species of Dinoderus by the following key:1. Elytra with an impunctate and glabrous part on declivity; antennae 10-segmented. Body length 3.5-4.0 mm ......... D.speculifer LESNE1'. Elytra without impunctate and glabrous part on declivity ......... 22. Antennae 10-segmented; 1st tarsal segment shorter or nearly as long as the 2 nd ; a median pair of tubercles on the pronotal anterior margin not so larger than others on its lateral sides ......... 32'. Antennae 11-segmented ; 1st tarsal segment longer than the 2nd ; a median pair of tubercles on pronotal anterior margin distinctly larger than others on its lateral sides. Body length 3.0-3.8 mm ...... D.japonicus LESNE3. Body slightly stout and large ; anterior margin on pronotum sinuate with nearly triangular teeth ; the teeth not contiguous to each other at the base. Body length 2.5-3.5 mm ......... D. minutus (FABRICIUS)3'. Body slender and small ; anterior margin of pronotum serrate with semicircular teeth ; the teeth contiguous to each other at the base. Body length 2.4-2.7 mm ......... D. bifoveolatus (WOLLASTON)Heterobostrychus aequalis may be distinguished from H.hamatipennis only hitherto known species of this genus from Japan by the following characters ; weakly impressed frontoclypeal suture, numerous and strong punctures on basal half of pronotum, smooth and glabrous scutellum, glabrous elytra, and in male two distinct horns on each elytral declivity.

Extensive pilot use of the grain protectant combinations, fenitrothion plus bioresmethrin and pirimiphos‐methyl plus bioresmethrin

AbstractEach of the combinations, bioresmethrin (1 mg kg−1) plus pirimiphos‐methyl(6 mg kg−1) or fenitrothion (12 mg kg−1), was applied in 1976 to grain in 21 commercial storages. Grain condition and protectant residues were regularly monitored. Three storages became infested with Rhizopertha dominica (F.), but all storages remained free of other insect species. In two of the three infested storages, application of protectant was uneven, and the third became infested only after 8 months of storage. Despite some variations in recovered residues between sites, the mean residue levels were accurately described by predictive models. Falls in temperature during storage varied considerably, and were related to factors other than climate and bin size. There was a marked effect by aeration with ambient cold air on both the grain temperature and the rate of loss of residues. Results of collaborative studies on the determination of residues indicate a need for regular check programmes of analysis, and confirm previous conclusions that residues of fenitrothion and pirimiphos‐methyl can be accurately and conventionally determined.

Storage of Cassava Chips (Manihot esculenta): Insect Infestation and Damage

SUMMARYInsects cause serious problems during the storage of cassava chips, when quality may be reduced and significant quantities of the product consumed. The major species naturally infesting chips were Rhizopertha dominica, Lasioderma serricorne and Araecerus fasciculatus. Infestation occurs during the sun-drying process, and up to 16% reduction in chip weight due to insect feeding was recorded after 2 months storage. Chips that had not received any pre-drying storage, but contained salt as a preservative, were infested by fewer insects than chips without salt. The poorest quality chips had significantly more insects than better quality ones.

Olfactory Responses to Milk Powder on Foodstuff Pests

The chemotaxis to milk powder on principal foodstuff pests were examined using the Y-tube olfactometer (Fig. 1).The samples tested were 14 species (Periplaneta fuliginosa, Blattella germanica, Trogoderma granarium, Oryzaephilus surinamensis, Cryptolestes minutus, Tribolium castansum, Lasioderma serricorne, Rhizopertha dominica, Sitophilus zeamais, S. oryzae, Cadra cautella, Ephestia kuhniella, Plodia interpunctella and Bracon hebetor).The experimental results were as follows: Attractive species was Bracon hebetor alone, and the other all species were ineffectiveness.