Dust Formulations Research Articles

Bio-efficacy and Persistence of Inert Dust Formulations as Stored-grain Protectants against Sitophilus oryzae (L.)


 
 
 Inert dust formulations of natural origin act as promising alternatives in controlling storage infestations caused by deleterious coleopteran insect pests. In that context, laboratory studies were conducted in order to evaluate the insecticidal activity, progeny inhibition and persistence of three commercially available dust formulations, namely, diatomaceous earth, zeolite and cloisite 20A against Sitophilus oryzae adults, a major coleopteran pest of stored grains, throughout 90 days of storage period. Adulticidal and persistence bioassays were conducted to evaluate the toxicity of binary combinations of inert dusts using their sub-lethal doses towards the test insect for 60 days of storage period. Further, ultrastructural architecture of the test insect pest species was examined via Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-Ray Analysis (EDX) to study the uptake/penetration pattern of inert dust particles through the cuticular layers of target insect pest. All inert dust formulations exhibited very efficacious toxic and progeny inhibition activities and extraordinary mortality percentages irrespective of the inert dust used at the end of initial 30 day-long storage period. Thereafter, mortality percentages gradually declined with the progress of the storage time period, declining in the order of, diatomaceous earth>zeolite>cloisite 20A. All the dust formulations successfully inhibited the progeny production and the lowest average progeny production was recorded at the end of initial storage period. Progeny inhibition decreased with the progress of storage time. Binary combinations of inert dust formulations exhibited additive and antagonistic effects against S. oryzae and similarly, the mortality percentages gradually decreased with the prolongation of the storage period. The FE-SEM and EDX micrographs clearly indicated the presence of dust particles and the distribution of their constituting elements on the cuticular layer of the exposed insect pests with the appearances of abrasions and scratches that may have led to dehydration and eventual death of S. oryzae. Thus, findings of the present study suggest that, naturally-derived diatomaceous earth, zeolite and cloisite 20A can be used as eco-friendly means as stored grain protectants against S. oryzae populations successfully in the storage grain systems.
 Keywords: Sitophilus oryzae, Diatomaceous earth, Cloisite 20A, Zeolite
 
 

Insecticidal Effect of a Natural Turkish Diatomaceous Earth Formulation on Greater Wax Moth

In this study, the insecticidal effect of the Detech® (Turkish Diatomaceous earth) DE formulation against Galleria mellonella L. was determined. The study was conducted in a laboratory environment with materials taken from beehives produced at Muş Alparslan University in 2022. Diatomaceous earth (DE) was applied in two different forms (dust and slurry DE) and as positive control GüveSavar®, which is currently used against some pests in beekeeping. DE concentrations of 0, 3, 5, and 7 g/m2 in different exposure times were tested for the control of G. mellonella larvae. As a result of all treatments, the highest mortality occurred at 7 g/m2 dust DE concentration. Larvae (3rd stage) exposed to 7 g/m2 concentration according to dust DE mortality rates reached 100% mortality after 40 hours. According to the results of the slurry DE, the larvae exposed to the slurry diatom at all concentrations achieved 100% mortality at the end of the 96 hours. When the dust and slurry DE results were examined, the direct use of dust formulations greatly accelerated the effectiveness against larvae. The study showed very promising results, suggesting that slurry DE and dust formulations could be a new alternative control method for Greater Wax Moth. In addition, for the first time, the insecticidal efficacy of DE against the honey bee pest, the greater wax moth, was determined.

The Effect of Botanical Pesticides Azadirachtin, Celangulin, and Veratramine Exposure on an Invertebrate Species Solenopsis invicta (Hymenoptera: Formicidae).

The injudicious and excessive use of synthetic pesticides has deleterious effects on humans, ecosystems, and biodiversity. As an alternative to traditional crop-protection methods, botanical pesticides are gaining importance. In this research endeavor, we examined the contact toxicity, knockdown time, lethal time, and toxicity horizontal transmission of three natural pesticides from plants (azadirachtin, celangulin, and veratramine) on red imported fire ants (RIFA; Solenopsis invicta). Our research findings indicated that azadirachtin and celangulin exhibited relatively high toxicity, with median lethal dose (LD50) values of 0.200 and 0.046 ng/ant, respectively, whereas veratramine exhibited an LD50 value of 544.610 ng/ant for large workers of S. invicta at 24 h post-treatment. Upon treatment with 0.125 mg/L, the (median lethal time) LT50 values of azadirachtin and celangulin were determined to be 60.410 and 9.905 h, respectively. For veratramine, an LT50 value of 46.967 h was achieved after being tested with 200 mg/L. Remarkably, azadirachtin and celangulin were found to exhibit high horizontal transfer among RIFA, with high secondary mortality (100%) and tertiary mortalities (>61%) after 48 h of treatment with 250 mg/L, as well as with their dust formulations for 72 h. However, veratramine did not exhibit significant toxicity or horizontal transfer effects on RIFA, even at high concentrations. These findings suggest that azadirachtin and celangulin are likely to have a highly prominent potential in the management of S. invicta.

Insecticidal Effect of Diatomaceous Earth Formulations for the Control of a Wide Range of Stored-Product Beetle Species.

Diatomaceous earth (DE) formulations are promising alternatives over the use of traditional insecticides. In the present study, a series of laboratory bioassays was carried out to assess the efficacy of three diatomaceous earth formulations, i.e., Silicid, Celatom® MN-23, and SilicoSec®, for the control of a wide range of stored-product insect species in soft wheat. The species tested were Tribolium confusum, Tribolium castaneum, Sitophilus oryzae, Sitophilus granarius, Rhyzopertha dominica, Oryzaephilus surinamensis, and Alphitobious diaperinus. Different dose rates, i.e., 0 (control), 100, 300, 500, and 1000 ppm, were used for each of the aforementioned dust formulations. Mortality levels of the exposed individuals were assessed after 3, 7, 14, and 21 days of exposure. Moreover, progeny were counted 65 days later. Based on our results, dust formulations were effective for the control of most of the stored-product beetle species tested. Among the DE formulations tested, Silicid could adequately control the stored-product insect species. Complete suppression of offspring was observed only for secondary species (T. confusum, T. castaneum, O. surinamensis, and A. diaperinus). For primary species (S. oryzae, S. granarius, and R. dominica), the lowest number of progeny was observed in wheat treated with Silicid. For instance, in the case of R. dominica, significantly fewer individuals were produced in Silicid-treated wheat at the highest dose rate. The results of the present study aim to encourage the utilization of DE in stored-product protection as an integrated pest management tool. Additional experimentation is required to apply the tested DE formulations in the field and on different surfaces.

Efficacy of Dust and Wettable Powder Formulation of Diatomaceous Earth (Detech®) in the Control of Tyrophagus putrescentiae (Schrank) (Acari: Acaridae).

Simple SummaryAcaricidal efficacy of two Turkish diatomaceous earth (DE) formulations (Detech® WP95 and Detech® Dust) were applied on a concrete surface at five different concentrations at 25 ± 1 °C and 75 ± 5% RH. Mite mortalities were observed after 6- and 18-hour exposure periods dust and WP formulations, respectively. In conclusion, our laboratory tests indicated that both WP and dust formulations of local diatomaceous earth can cause 100% mortality in 24 h on average and can be a promising alternative to conventional chemical acaricides.Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous earth (DE) formulations (Detech® WP95 and Detech® Dust) were applied on a concrete surface at five different concentrations (1, 2.5, 5, 7.5, and 10 g/m2) and dead individuals were counted at 11 different time intervals (1, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 h) at a temperature of 25 ± 1 °C and 75 ± 5% relative humidity (RH). Mite mortalities were observed after 6- and 18-hour exposure periods at all concentrations of dust and wettable powder (WP) formulations, respectively. Specifically, 100% mortality for the WP formulation was achieved at the highest concentration of 10 g/m2 after 15 h of exposure and after 27 h and 30 h for the lowest concentration. In the case of dust formulation, mortalities were observed after 3 h of exposure at all concentrations except at 1 g/m2, while a 100% mortality rate was achieved after 21 h of exposure to all concentrations and after 18 h of exposure for 7.5 g/m2 and 10 g/m2. This study indicates that both WP and dust formulations of local diatomaceous earth can cause 100% mortality in 24 h on average and can be a promising alternative to conventional chemical acaricides.

Insecticidal Effect of an Enhanced Attapulgite for the Control of Four Stored-Product Beetle Species

We examined the insecticidal effect of three different dust formulations, which were attapulgite (W), attapulgite mix with oregano essential oil with 52% carvacrol (D1), and attapulgite mix with oregano essential oil with 75% carvacrol (D2), in four major stored-product beetle species, Sitophilus oryzae (L.), Tribolium confusum Jacquelin du Val, Rhyzopertha dominica (F.), and Trogoderma granarium Everts. Sitophilus oryzae was the most susceptible at all three formulations, followed by T. confusum and R. dominica. In contrast, T. granarium larvae showed the lowest mortality rates even on the 14th day of observation and at the highest concentration (2000 ppm). Progeny production was particularly reduced for all species relative to the controls. Nevertheless, complete suppression of the offspring was observed only in the case of T. confusum and S. oryzae, while R. dominica was less susceptible to all three dust formulations, giving an average of up to 20 individuals per vial at 2000 ppm. To our knowledge, this study is the first that has examined the insecticidal activity of oregano compounds in combination with attapulgite for the control of stored-grain insect species. Additional experimentation is required to indicate the rationale of using these natural resource-based materials under a non-chemical control strategy at the post-harvest stages of agricultural commodities.

Efficacy of Piper guineense (Shum and Thonn), Dennettia tripetala (G. Baker), and Ocimum gratissimum (Linnaeus) powders admixed with selected excipients for the control of Callosobruchus maculatus (Fabricus) infesting cowpea, Vigna unguiculata (L. Walp), seed

The use of synthetic insecticides to control stored product insects causes various health and Ecological challenges to man. Therefore, there is a need for alternative formulations like plant materials with the least possible side effects for the effective control of cowpea bruchid, Callosobruchus maculatus (Fabricius), a cosmopolitan pest of pulses. This study evaluated the efficacy of insecticidal dust formulations using three botanicals (Piper guineense, Dennettia tripetala and Ocimum gratissimum), three excipients (rice bran, maize husk and cowpea pod husk), admixed at ratios 70:30, 60:40, 50:50, 40:60 and 30:70 botanical to an excipient, for the control of C. maculatus. Four particle sizes (212, 300, 500 and 1000 µm) applied at dosages of 0.1- 0.5 g / 20 g cowpea seeds were assayed and untreated cowpea seeds served as controls. Ten C. maculatus adults (sex ratio 1:1) were used to infest the treated and untreated cowpea seeds separately in Petri dishes. Data were collected on mortality, Oviposition, F1 progeny emergence and damaged cowpea seeds. The data were subjected to analysis of variance and means were separated with Least Significant Difference at a 5% significance level. All dosage ratios of the formulated dusts caused significantly (p˂ 0.05) higher mortality of bruchids, reduced the number of laid eggs, F1 progeny emergence and damaged cowpea seeds due to C. maculatus infestation. Regardless of the assayed botanical, 212 µm particle size was outstanding and the formulation ratio of 70:30 (botanical: excipient) was significantly (p˂ 0.05) better than other formulation ratios. The formulation with P. guineense with any excipient at 0.5 g/ 20 g cowpea seeds using 212 µm was superior to other formulations as cowpea protectant against C. maculatus. Therefore, it is recommended as an alternative to over-dependence on synthetic insecticides.

Laboratory development and pilot-scale deployment of a two-part foamed rock dust

U.S. Code of Federal Regulations 30 CFR 75.402 and 75.403 require 80% total incombustible content to be maintained within 40 feet of the coal mine face via the liberal application of rock dust. Unfortunately, this application of rock dust limits miners' visibility downwind and can increase the miners' exposures to a respirable nuisance dust. Wet rock dust applied as a slurry is, at times, used to negate these negative effects. Although this aids in meeting the total incombustible limits, the slurry forms a hard cake when dried and no longer effectively disperses as needed to suppress a coal dust explosion. As a result, a dry rock dust must be reapplied to maintain a dispersible layer. Therefore, researchers from the National Institute for Occupational Safety and Health (NIOSH) have been working towards finding and testing a foamed rock dust formulation that can be applied wet on mine surfaces and remain dispersible once dried which minimizes the likelihood of mine disasters, including mine explosions. The initial tests were aimed at discerning dispersion characteristics of three different foamed rock dusts via the NIOSH-developed dispersion chamber and led to identification of a two-part foam with adequate dispersion characteristics. The current study was conducted to assess the robustness of the two-part foamed rock dust. Through a series of laboratory-scale experiments using the dispersibility chamber, the effects of testing conditions and product formulations on the foam's dispersibility was determined. Some of the tested variables include: exposing the foam to high humidity, varying the component levels of the foamed rock dust, altering the rock dust size distribution, and varying the rock dust types. Further pilot-scale tests examined the atmospheric concentrations of dust via personal dust monitors downwind of foamed rock dust production and application. Additionally, product consistency was recorded during pilot-scale testing at key points in the formulation and application. The results of these experiments will be discussed in this paper.

Lethal Effects of Commercial Kaolin Dust and Silica Aerogel Dust With and Without Botanical Compounds on Horn Fly Eggs, Larvae, Pupae, and Adults in the Laboratory.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important bloodsucking ectoparasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic insecticides but as concerns about resistance increase, alternative tactics have come under heightened scrutiny. Four desiccant dust products: Surround WP, a kaolin clay-based wettable powder; CimeXa, comprised of silica aerogel; Drione, silica aerogel + pyrethrins; and EcoVia, silica aerogel + thyme oil, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround WP and CimeXa did not prevent egg hatching and (when mixed with manure substrate) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality within 6 hr and 24 hr, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 hr, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.

Protecting Plant Stands: Peanut Industry Moves Quickly to Address Emerging Disease Threat

AbstractUniform stands of 4 plants/ft are recommended for runner peanuts to obtain maximum yield and manage stand‐sensitive diseases such as tomato spotted wilt virus that can cause serious crop loss. Numerous seed‐ and soil‐borne diseases can threaten stands if not controlled. With increasing heat and drought stress, such as experienced in 2019, Aspergillus is of particular concern. Seed treatment fungicides are the first line of defense, but the unexpected development of resistance to a key fungicide class (QoIs) just prior to planting in 2020 caused the industry to rapidly alter its standard programs. Another major industry change is a shift from dust formulations to a liquid polymer delivery system. Earn 0.5 CEUs in Integrated Pest Management by reading the article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/980.

Yerli Diyatom Toprağının Patates Güvesi [Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)] Pupasına Karşı Böcek Öldürücü Etkisi

In this study, the insecticidal activity of native diatomaceous earth (DE) Turco004 was tested against pupae of the Potato tuber moth, [Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)] in laboratory conditions. In the bioassays were used dust formulation and applied four concentrations (2.5, 5, 10 and 20g/m2) of DE. Pupa weights and the number of adults emerging from the pupae were recorded after 24, 48, 72, 96, 120, 144 and 168 hours of diatomaceous earth exposure. It was concluded that the weights of the pupae are significantly affected depending on exposure time. In addition, pupal eclosion was prevented, and no adult emergency was observed at all concentration applied. The data obtained revealed that the native diatom soil Turco004 may have a potential in the control of P. operculella at all applied doses.

Evaluation of a Non-Chemical Compared to a Non-Chemical Plus Silica Gel Approach to Bed Bug Management.

Bed bug resistance to commonly used pesticide sprays has led to exploring new pesticides and other strategies for bed bug management. Non-chemical methods are effective in bed bug management; however, they do not provide residual protection. Compared to insecticide sprays, dust formulations are considered to provide longer residual control. We evaluated two bed bug management programs in apartment buildings. A building-wide inspection was initially conducted to identify bed bug infested apartments. Selected apartments were divided into two treatment groups: non-chemical plus silica gel dust treatment (10 apartments) and non-chemical treatment (11 apartments). After initial treatment, apartments were re-visited monthly for up to 6 months. During each visit, the total bed bug count per apartment was obtained by examining interceptor traps placed in the apartments and conducting a visual inspection. Mean bed bug count was reduced by 99% and 89% in non-chemical plus silica gel dust and non-chemical treatment, respectively. Non-chemical plus silica gel dust treatment caused significantly higher bed bug count reduction than the non-chemical treatment at 6 months. Bed bugs were eradicated from 40% and 36% of apartments treated with non-chemical plus silica gel dust treatment and non-chemical treatment, respectively.

Assessment of different inert dust formulations for the control of Sitophilus oryzae, Tribolium confusum and Aphis fabae

The necessity to ensure the quality of food by simultaneously reducing the environmental footprint due to the extensive use of convectional insecticides has led to an increase in the efforts towards the development of non-chemical control strategies. Silicon dioxide is considered as a promising alternative active ingredient for the control of various arthropods in different crops and products. Silicon dioxide and the relative silicaceous materials (silica) are classified in the category of inert dusts, which act on arthropods through contact leading to desiccation. In our study, we tested three different silica-based dust formulations, Sylobloc® S200, Syloid® ED3 and Syloid® ED5 in order to evaluate their pest control efficacy. As target species, we used, in laboratory bioassays, a field/greenhouse pest the aphid Aphis fabae and the stored-product pests Tribolium confusum and Sitophilus oryzae. These species were exposed to the aforementioned dusts under three different doses (0, 12.5, 25.0 mg/petri) and different time intervals. Taking into account the exposure time of the above species to the inert dusts, S. oryzae adults and T. confusum larvae were more susceptible to ED5 at 25.0 and 12.5 mg, respectively, while A. fabae adults to S200 at the highest tested dose, since less time was needed in order to achieve the highest mortality. Sitophilus oryzae and T. confusum mortality was increased to 90% after the 7th day of post exposure period to all dust formulations, while the highest mortality levels of A. fabae were recorded after 1 day of post exposure to S200. The results of this study show that these silicon dust formulations are effective to greenhouse and storage insect control and can be further exploited through various uses, e.g. in insect-proof nets to minimize the pest invasions in greenhouses.

Effect of Moisture on Efficacy of Selected Insecticide Dusts Against the Common Bed Bug, Cimex lectularius (Hemiptera: Cimicidae).

Insecticide dust formulations are considered as more effective for controlling the common bed bug, Cimex lectularius (L) (Hemiptera: Cimicidae), than residual sprays. Various environmental factors may affect the efficacy of insecticide dusts. In this study, we evaluated the effect of moisture on the efficacy of three insecticide dusts against C. lectularius. Moisture was created using two methods: applying steam to insecticide dust-treated tiles and aging insecticide dust-treated tiles in chambers with various levels of relative humidity (RH). In the steam treatment, three insecticides including Cimexa (92.1% amorphous silica gel), Alpine (0.25% dinotefuran, 95% diatomaceous earth), and Tempo (1% cyfluthrin) were evaluated. Exposure to steam significantly reduced the efficacy of all three insecticide dusts. Among the three insecticides, the efficacy of Cimexa was significantly higher than Alpine and Tempo. In the different RH treatments, Cimexa treated tiles that were aged under different (52, 75, and 100%) RH conditions for 1 and 2 mo caused significantly lower mortality to C. lectularius than nonaged Cimexa. We conclude that both, a short period of exposure to steam and long-period aging in a moist environment, can significantly reduce the efficacy of insecticide dusts. Moisture needs to be considered when applying insecticide dusts for controlling bed bug infestations.

Evaluation of Neem Dust Formulations for the Control of Sorghum Stemborers in the Semi-Arid Zone of Nigeria

Sorghum stemborer species remains key yield limiting factor for sorghum production in the Nigerian semi-arid region. When they can afford, farmers rely almost solely on synthetic insecticides for control. Owing to the misuse and environmental and health challenges attributed to the use of synthetic insecticides, a two-year field study was carried out at the University of Maiduguri Research Farm to evaluate the efficacy of various neem dust formulations for the control of Sorghum stemborers. The experimental design was Randomized Complete Block Design and various neem dust formulations were compared with carbaryl dust and the control (untreated). All the insecticide treatments significantly (p < 0.05) reduced stalk and peduncle damage caused by stemborers with a resultant increase in grain yield when compared with the control. Neem Kernel Powder (NKP) + Finesand proved more superior in efficacy than all the other insecticide treatments in checking stemborer damage.

Effect of dust formulation of milkweed (Calotropis gigantea R. Br.) different plant parts against Helicoverpa armigera (Hubner)

Helicoverpa armigera (Hubner) (Noctuidae: Lepidoptera) is known as American bollworm and is one of the most destructive pests of various crops and more or less of universal occurrence except in regions where extremes of climate prevails. It has been reported to feed on more than 120 cultivated food plants all over the world. Host species for H. armigera come from a broad spectrum of families and include important agricultural crops such as cotton, maize, chickpea, pigeon pea, sorghum, sunflower, soyabean and groundnuts. Management of H. armigera using insecticides has become difficult because of the development of resistance. Therefore alternate measures of control that are more efficient, more economical and safer need to be developed. Botanical insecticides have long been touted as attractive alternations to synthetic chemical insecticides for pest management. Taking all these into consideration, investigations were undertaken to obtain precise information on the effect of C. gigantea plant parts on different developmental stages of H. armigera. Fresh Calotropis gigantea R. Br plant parts viz., leaves, stem, flower and roots were collected and allowed to shade dry to prevent the loss of active principle from the plant parts. The shade drying process was continued until the plant materials were dried enough to be powdered. The dried plant materials were taken individually and ground into powder with the help of a Willey mill. The percent mortality of second instar larvae of H. armigera was directly proportional to the concentration of plant part dust. The leaf dust proved its superiority over other plant parts dust by giving 86.66% of mortality at 10% concentration followed by 8% (60.00%), 6% (53.33%), 4% (43.33%) and 2% (33.33%) mortality, respectively. Followed by flower dust treatment recorded the maximum mortality of 66.66% at 6%. Next to flower dust, the whole plant dust and stem dust evinced maximum mortality at 10% concentration (63.33 and 43.33%), root dust exerted low mortality percentage in 2% concentration. Leaf dust at 10% recorded maximum mortality rate of 83.33% against third instar larvae whereas 8, 6, 4 and 2% recorded mortality of 76.66, 46.66, 40.00 and 26.66%, respectively. Next to leaf extract, flower and whole plant dust at 10% concentration proved its superiority by causing 76.66 and 73.33% mortality, respectively. Stem dust showed the maximum mortality at 10% (56.66%). Root dust was found to be least effective.

Entomotoxic effect of silicon dioxide nanoparticles on Plutella xylostella (L.) (Lepidoptera: Plutellidae) under laboratory conditions

ABSTRACTThe use of higher dosage and repeated applications of conventional pesticides have led to the rapid development of insect resistance to pesticide and adverse effects on human health and environment. Accordingly, researchers are prompted to identify an alternative entomotoxic agent for crop protection. Nanocides are being considered as alternatives to conventional insecticides because they are expected to lessen the application rate and reduce the chances of resistance development in pests. In this study, we evaluated the entomotoxic effects of nanosilica on larvae of Plutella xylostella, in a laboratory by using dust spray, larva dipping, leaf dipping, and solution spray methods. Dust treatment showed a more highly significant effect than the other three treatments. The mortality percentage increased up to 58% and 85% at 24 and 72 h after treatment, respectively, when nanosilica was applied at a rate of 1 mg cm−2. In all four bioassays, mortality rate increased with both increased time after nanosilica exposure and increased concentration. Light microscopy and scanning electron microscopy images showed that larval death was due to desiccation, body wall abrasion, and spiracle blockage. These results suggested that nanosilica can be an alternative to conventional pesticides if dust formulation would be properly used.

Effectiveness of Selected Entomopathogenic Fungi in Packed Rice Grain at Room Temperature Against Corcyra Cephalonica Stainton

Eight isolates of entomopathogenic fungi were evaluated as dried conidia against the rice moth, Corcyra cephalonica. In bioassays two isolates of Beauveria bassiana (BbGc and BbPs) and one isolate of Metarhizium anisopliae (MaPs) consistently gave high mortality to C. cephalonica larvae. Formulations in either kaolin, talc or tapioca flour (20 % w/w a.i.) thoroughly mixed with long grain rice in plastic cups (8 cm diameter by 5 cm) gave complete larval mortality by the 12th day of treatment. However, in general those formulated in kaolin and talc were more efficacious and faster to kill compared to those formulated in tapioca flour or the unformulated control. Even at the lowest rate of 0.05 g BbGc in kaolin provided 100% mortality 7 days after introduction compared with other dust formulations. Isolate BbGc in kaolin and talc administered at 0.4 g a.i. in 200 g rice packed in plastic kept at room temperature provided protection against the rice moth up to 4 months of storage. Larval mortality in excess of 90% was obtained 15 days after introduction. Formulations of MaPs was effective only within the first month of storage beyond which infectivity rapidly declined.

Effect of Baculovirus with adjuvants against Helicoverpa armigera (HBN) on Cotton and evaluation of its effect in Different Instar

During the past few years, the damage by the American bollworm Helicoverpa armigera (Hbn) has become serious on many crop plants especially cotton in South India. Along with that insecticide resistance varieties of larvae were also reported. In our study, field-collected larvae were reared in glass vial providing tender leaves for neonatal larvae and squares of grown up larvae. The along with the adjuvants were made into wettable and dust formulation and were studied. Evaluation of the Efficacy of Helicoverpa NPV with certain adjuvants possessing phagostimulants in combination were tested in different instars and results were tabulated.

Comparative Efficacy of Selected Dust Insecticides for Controlling Cimex lectularius (Hemiptera: Cimicidae).

Bed bugs, Cimex lectularius L., are one of the most difficult urban pests to control. Pest management professionals rely heavily on insecticide sprays and dusts to control bed bugs. Dust formulations are considered to provide longer residual control than sprays. However, there are no scientific data available on the comparative efficacy of the commonly used insecticide dusts. We evaluated the efficacy of eight insecticide dust products using three exposure methods: 1) brief exposure-bed bugs crossed a 2.54-cm-wide dust-treated band, 2) forced exposure-bed bugs were continuously exposed to a dust-treated substrate, and 3) choice exposure-bed bugs were given a choice to stay on either dust-treated or untreated substrate. The brief exposure method was the most sensitive in detecting the differences among the insecticides. Only CimeXa (silica gel) dust caused 100% mortality from all three exposure methods. Other tested dusts (1% cyfluthrin, 0.05% deltamethrin, 0.075% zeta-cypermethrin + 0.15% piperonyl butoxide, 1% pyrethrins, 1% 2-phenethyl propionate + 0.4% pyrethrin, 0.25% dinotefuran + 95% diatomaceous earth, 100% diatomaceous earth) caused ≤65% mortality in a brief exposure assay. We also evaluated the horizontal transfer effect of the silica gel dust. Silica gel dust-exposed bed bugs transferred the dust horizontally to unexposed bed bugs resulting in 100% mortality at 4:6 donor: recipient ratio and 88.0 ± 5.0% mortality at 1:5 donor: recipient ratio. The results suggest silica gel is the most promising insecticide dust for controlling C. lectularius.