Soil Insect Control Research Articles

An alginate-based encapsulation enhances shelf life and bioactivity of the entomopathogenic fungus, Metarhizium anisopliae

BackgroundThis study evaluated the shelf life and effectiveness of Metarhizium anisopliae encapsulated in Na (sodium)-alginate matrix. Air-flow-dried and freeze-dried beads containing conidia of M. anisopliae produced in submersion in the liquid broth were fabricated and characterized. Shelf life and efficacy of fabricated beads against three species of the white grubs, namely Holotrichia serrata, Adoretus sp., and Lepidiota mansueta, were evaluated under greenhouse conditions.ResultsThe mean size of the wet beads ranged between 1.4 and 3.2 mm. The mean size of beads that were dried through freeze drying ranged between 0.55 and 2.3 mm. However, the mean size of beads dried through air flow ranged between 0.55 and 2.35 mm. Viability of M. anisopliae was more in freeze-dried beads stored at 8 °C compared to air-flow-dried beads with 20.0 × 107 and 16.00 × 107 CFU/g, respectively, after two weeks of drying. Further, freeze-dried beads supported M. anisopliae conidial viability till 10 months with 2.0 × 107 CFU/g. The LC50 values of the freeze-dried beads with M. anisopliae after 21 days of treatment were 0.35 (2.1 × 108 CFU/g), 0.31 (2.1 × 108 CFU/g), and 0.76 mg (2.1 × 108 CFU/g) against H. serrata, Adoretus sp., and L. mansueta, respectively.ConclusionThe results of this study support the use of Na-alginate beads followed by freeze drying to maintain the viability of M. anisopliae. The effectiveness of freeze-dried beads with M. anisopliae against white grubs indicates that these beads can be an alternative option of synthetic insecticides against soil dwelling insect pests. In addition, this study offers a steppingstone for further advancement of sodium alginate encapsulated formulations for soil insect control.

Transcriptome Profile Changes Associated With Heat Shock Reaction in the Entomopathogenic Nematode, Steinernema carpocapsae.

The entomopathogenic nematode Steinernema carpocapsae has been used for control of soil insects. However, S. carpocapse is sensitive to environmental factors, particularly temperature. We studied an S. carpocapse group that was shocked with high temperature. We also studied the transcriptome-level responses associated with temperature stress using a BGIseq sequencing platform. We de novo assembled the reads from the treatment and control groups into one transcriptome consisting of 43.9 and 42.9 million clean reads, respectively. Based on the genome database, we aligned the clean reads to the Nr, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases and analyzed the differentially expressed genes (DEGs). Compared with the control, the heat-shocked group had significant differential expression of the heat shock protein (HSP) family, antioxidase [glutathione S-transferases (GSTs) and superoxide dismutase (SOD)], monooxygenase (P450), and transcription factor genes (DAF-16 and DAF-2). These DEGs were demonstrated to be part of the Longevity pathway and insulin/insulin-like signaling pathway. The results revealed the potential mechanisms, at the transcriptional level, of S. carpocapsae under thermal stress.

Zamorano y sus Contribuciones a la Agricultura Sostenible a Través del Control Biológico de Plagas

El Centro para el Control Biológico en Centro América (CCBCA) fue creado en 1989 por la Escuela Agrícola Panamericana, financiado por la United States Agency for International Development (USAID) en Honduras. El CCBCA se enfocó en el control biológico clásico, el aumento y la conservación de enemigos naturales. En el 2000 cambió el nombre de Laboratorio de Control Biológico y se enfocó en el aprender haciendo de los estudiantes de la Escuela Agrícola Panamericana y la producción y comercialización de enemigos naturales de plagas agrícolas. El único parasitoide conocido que ataca al picudo de las bromelias (Metamasius quadrilineatus), fue encontrado en las investigaciones del CCBCA; resultó una especie nueva nombrada Lixadmontia franki que fue liberada en Florida en el 2007 para el control biológico del picudo mejicano de las bromelias (Metamasius callizona). Se determinaron los organismos parasíticos de las plagas Plutella xylostella, Mocis latipes, Spodoptera frugiperda, Leptophobia aripa y Liriomyza spp. Cuatro especies de avispas parasíticas exóticas, un baculovirus, un hongo y tres picudos fueron introducidos a Honduras para control biológico clásico: Cotesia plutellae (parasitoide asiático de P. xylostella); Diadromus collaris (parasitoide pupal de P. xylostella); Telenomus remus (parasitoide que ataca a los huevos de 30 especies de lepidópteros); una especie de Eretmocerus (originaria de India, para controlar Bemisia tabaci); los picudos Neochetina bruchi y Neochetina eichhorniae y el hongo Cercospora piaropi (para el control de la maleza acuática lirio de agua (Eichhornia crassipes); y el picudo Neohydronomous affinis (controlador biológico de la maleza acuática lechuga de agua (Pistia stratiotes). En el 2000, Zamorano cambió la estrategia del uso de control biológico y empezó a incursionar en la producción comercial de microrganismos para el control de plagas, debido a una demanda no satisfecha. Los controladores biológicos que ha producido son el hongo antagonista Trichoderma harzianum (Trichozam™) para combatir hongos en el suelo, Beauveria bassiana (Bazam™) para controlar lepidópteros y coleópteros, Lecanicillium lecanii (Verzam™) para el control de áfidos y mosca blanca, Metarhizium anisopliae (Metazam™) para el control de salivazo (Aeneolamia spp.) y larvas de coleópteros en caña de azúcar, y Purpureocillium lilacinum (Pazam™) para controlar nematodos. Además, ha reproducido y vendido la chinche depredadora Orius insidiosus para el control de trips, áfidos y mosca blanca, el ácaro depredador Neoseiulus longispinosus para el control de la arañita roja (Tetranychus spp.) y el nematodo entomófago Heterorhabditis bacteriophora para el control de insectos del suelo, especialmente contra Phyllophaga spp., Cosmopolitus sordidus, larvas de lepidóptera, picudo del camote (Cylas formicarius) y termitas en el suelo. Posiblemente, el mayor aporte es en la enseñanza de las técnicas y tecnologías del control biológico de plagas que se han distribuido por América Latina a través de los graduados de Zamorano que estudiaron y fueron entrenados en Zamorano.DOI: http://dx.doi.org/10.5377/ceiba.v52i1.966

Virulence of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of Diabrotica speciosa germar (coleoptera: chrysomelidae)

Entomopathogenic nematodes (EPNs) are used in biological control of soil insects and show promise in the control of D. speciosa. The objective of this work was to evaluate the potential of native and exotic entomopathogenic nematode isolates in the control of D. speciosa under laboratory and greenhouse conditions. Results showed that all of EPNs caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri (84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis amazonensis RSC05 (78%). There was no effect of the Heterorhabditis sp. RSC01 and S. glaseri isolates on eggs. The maximum mortality of D. speciosa larvae by Heterorhabditis sp. RSC01 was observed at a concentration of 300 IJ/ insect, while by S. glaseri observed the highest mortality at the concentration of 200 IJ/ insect. The Heterorhabditis sp. RSC01 isolate caused over 80% pupal mortality at a concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was affected by temperature. The Heterorhabditis sp. RSC01 isolate caused reduction in larva survival under greenhouse conditions at all of the tested concentrations and there was no difference in mortality among different concentrations of infectid juveniles.

Combined effect of Azadirachta indica and the entomopathogenic nematode Steinernema glaseri against subterranean termite, Reticulitermes flavipes

Laboratory study has been conducted on the bioactivities of entomopathogenic nematodes and neem seed kernel extract (NSKE) against worker termites of <em>Reticulitermes flavipes</em>. Neem at various concentrations did not affect the survivability of nematodes, whereas neem had considerable impact on the survivability of worker termites and this may be due to the presence of active neem compounds (Azadirachtin, salanin etc.). Mortality was 40% on 4th day at lower concentration of 1.0% NSKE treatment; whereas mortality has been increased to 70% at higher concentration (4.0%) on 4th day. There was 100% mortality after the combined treatment with 4.0% NSKE + 600 infective juvenile <em>Steinernema glaseri</em>, even at the first day of the experiment. In the present experiment, neem extract does not affected the survival of the nematodes. Hence, nematode and neem extract can be used for soil-insect control particularly for the subterranean termites.

Entomopathogenic nematodes, a potential microbial biopesticide: mass production and commercialisation status – a mini review

Parasitic nematodes have several important attributes that make them excellent candidates for biological control of soil insects. These nematodes can be produced by in vivo by baiting technique on insects and commercially by in vitro solid/liquid culturing. Numerous insect pests on many different crops are being controlled by these insect parasitic nematodes, including root weevils, flea beetles, mint root borer, colorado potato beetle, white grubs, caterpillars and plant parasitic root nematode, e.g. root-knot nematodes. Utilisation of entomopathogenic nematodes (EPN) has raised intense interest and has been a growing concern globally mainly because of its potential efficiency, exemption from registration and other impressive attributes for utilising against the control of soil dwelling pests. This review highlights the mass production, commercialisation and utilisation of EPN as microbial biopesticide in bio-intensive pest management programmes.

Tobacco Aphid Control in Flue-Cured Tobacco, 1996

Abstract Flue-cured tobacco, variety K-326, was transplanted on 11 Apr 1996 at the Georgia Coastal Plain Experiment Station Entomology Farm. Production practices were used according to Georgia Cooperative Extension Service guidelines and included a preplant tank mixture of Tillam and Devrinol for weed control, Ridomil for blue mold control, Lorsban for soil insect control, and Nemacur for nematode suppression. Fertilizer (6-6-18) was applied in a split application at a rate of 1000 pounds/acre. Plots two rows wide (36 inch row spacing) by 20 ft long were arranged in a randomized complete block design with four replications. Plots were separated on each side with one un-treated border row and on each end with an alley 6 ft wide. Two Orthene at transplant treatments were applied in the transplant water at transplanting. On 27 May, 4 foliar insecticide treatments were applied using a CO2-powered backpack sprayer equipped with 3 TX-12 nozzles directed over a single row, delivering 29.9 gpa at 40 psi. The number of live aphids on plants 2, 4 and 6 of the left hand row was recorded from each plot prior to treatment (Pre-t) and 4,7 and 14 days after treatment (DAT). All plants were harvested on 17 Jun and 25 Jun, then weighed. All data were subjected to analysis of variance and the means were separated using Duncan’s multiple range test (P = 0.05).

Comparison of Various Soil Insecticides And Foliar Sprays for Soil Insect Control in Sweet Pota-Toes, Painter, Va, 1995

Abstract Sweet potatoes were transplanted on 20 Jun at the Eastern Shore Agricultural Research and Extension Center, Painter. VA. Each plot consisted of 3 rows 20 ft long, planted on 3 ft row spacing. An untreated guard row separated each plot from each other. Treatments were replicated 6 times in a RCB design. In furrow and band treatments, and the initial foliar sprays were applied with a single nozzle boom backpack sprayer. Granular treatments were applied with a hand held shaker. The Mocap treatments were applied on 25 May to avoid phytotoxicity. The later foliar sprays were applied with a backpack sprayer using 6 flat fan nozzles/row and delivering 42 gal water/acre at 40psi. Thiodan sprays were applied on 7, 14, and 21 Jul. Sevin XLR was sprayed on 27 Jul in order to observe the restrictions on the number of applications allowed on the Thiodan label. Foliar sprays were applied in order to coincide with clickbeetle (adult wireworm) flights, as determined by the black light trap at Painter, VA. Layby treatments were applied on 26 Jul. On 11 Oct, the center row of each 3 row plot was harvested and 25 market sized roots were randomly selected, washed, and evaluated for insect damage.

Soil Insect Control in Sweet Potatoes, Virginia, 1992

Abstract Sweet potatoes were transplanted on 18 May in a commercial field owned by J. H. Drewer & Sons near Painter, VA. Each plot consisted of 3 35 ft rows bordered on each side by an untreated row with 3 ft between rows. Each treatment was replicated 4 times in a randomized complete block design. Sprays were applied with a 5 nozzle flat fan boom backpack sprayer delivering 17 gal water/acre at 40 psi. Temik was applied in a 12 inch band with a hand-held shaker. The water volume for the Sevin foliar sprays was increased to 35 gal/acre on 10 Aug after the vines began to run. Foliar sprays were initiated when flights of wireworm adults were observed in the black light trap operated at Painter, VA. Treatments were applied on the dates indicated in the table. The center row of each plot was harvested on 8 Oct and yields (50 lb bu/acre) were determined. Twenty-five roots were randomly selected from the marketable roots in each plot and evaluated for insect damage. Damage due to Wireworm, Southern corn rootworm (Diabrotica) and Systena flea beetle feeding was analyzed together as WDS complex.

Potential for Biological Control of Soil Insects in the Caribbean Basin Using Entomopathogenic Nematodes

The numerous species and geographic isolates of entomopathogenic nematodes have a diversity of biological attributes which make them adaptable to many uses, especially management of soil pests. Entomopathogenic nematodes are viable substitutes for soil insecticides due to wide host range, persistence, mobility, safety, ease of application, and absence of registration restrictions. Efficacy is often comparable to chemical insecticides, which tend not to perform well in soil. Although soil is generally a very suitable habitat for nematodes, abiotic and biotic constraints are serious impediments in some locales. Surveys should be conducted in Caribbean countries to identify pre-adapted strains. Recent advances have made nematodes more economic to produce, and storage life has been extended. Entomopathogenic nematodes are appropriate for the Caribbean Basin environment due to favorable soil, humidity and temperatures, occurrence of hosts throughout most of the year, and a high incidence of damage caused by coleopterans and lepidopterans--pests which are usually quite susceptible to infection. In vitro production methods, which require medium-level technology and low cost labor, may be particularly suitable for the Caribbean.

Potential for Biological Control of Soil Insects Using Microbial Pesticides in the Caribbean

The negative environmental impact of chlorinated hydrocarbons and the potential for ground water contamination by the more soluble organophosphate pesticides have increased governmental and industrial support to development of microbial insecticides for soil insect management. There are many factors that must be considered when developing a pathogen for use in agricultural systems to control insect pests. Major factors include cropping system, target insect, soil type, and the pathogen itself. This paper addresses each of these factors and the influence they have on the success of an applied microorganism.

Evaluation of the Nematode Steinernema carpocapsae to Control Fire Ants in Nursery Stock

Recent developments in low-cost, large scale production of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis (Bedding 1984) have facilitated large-scale field testing against various soil-infesting insects (Kaya 1985, Poinar 1986), with good potential for control in some applications. Early research by Poole (1976) and Quattlebaum (1980) indicated that the potential included fire ants. Citrus growers in Florida using nematodes (BioVectorg; Biosys, Inc.) for control of soil insects have reported fewer problems with fire ants (personal communications to W. R. Martin). Jouvenaz et al. (1990), however, did not achieve significant control of red imported fire ants, Solenopsis invicta Buren, in field trials of nematodes (Biosys, Inc.) conducted in Florida. Steinernematid nematodes may be moderately effective against fire ants in irrigated soil. Morris et al. (1990) reported 47% control with Steinernema carpocapsae versus 39% control with the Amdro standard at sites containing irrigated turf. This level of control is far below normal for Amdro (Williams et al. 1987; Jouvenaz et al. 1990), indicating that it may have been broadcast on wet soil (personal communication, D. F. Williams, USDA, ARS). Unmarked mounds found outside the blocks after treatment were not included in the assessment for activity; thus, control by nematodes may have been overestimated due to mound relocation. Considerable relocation of fire ant nests occurred in the tests conducted by Jouvenaz et al. (1990). Had not mound movement been taken into consideration (Poole and Quattlebaum scored all mounds uninhabited after treatment as dead), the apparent control would have been over 77% (of 44 treated mounds, 34 were inactive). We subsequently confirmed the aversion of fire ants to nematodes by controlling the movement of small laboratory colonies between containers of sandy soil with single applications of BioSafe? Lawn and Garden Insect Control (Steinernema carpocapsae; Biosys, Inc., Palo Alto, CA). The readiness with which fire ants relocated their nests in the field and vacated soil in containers to avoid nematodes prompted us to evaluate the potential of these parasites to eliminate fire ants from nursery stock. The early spread of fire ants in the southeastern United States was greatly facilitated by the shipment of infested nursery stock (Lofgren 1986). Recently these pests have been transported to Arizona and California; if they become established in the West, their range will increase substantially. Currently, federal certification of nursery stock for shipment through quarantine is based solely on incorporation of chlorpyrifos. Granular chlorpyrifos is not as effective as previously believed, drenching poses problems of worker exposure, and both treatments are expensive (personal communication, H. Collins, USDA, APHIS). The improvement of methods for control of fire ants is a critical need of the nursery industry (Regelbrugge 1991). In the present study, three sequential tests were conducted using BioSafe against fire ants nesting in nursery pots containing Pittosporum sp. shrubs. A colony of S. invicta consisting of five queens, 3,000-5,000 workers and about 1.5 g brood was introduced into each of 50 1 gal pots containing shrubs 20-35 cm in height. The ants were

Soil-insecticide bioassays and seed treatments for soil-insect control in Central Queensland, Australia

Twelve insecticides were tested as seed treatments or as banded applications in laboratory soil bioassays against striate false wireworm larvae ( Pterohelaeus alternatus Pascoe). The systemic carbamate insecticides carbofuran and furathiocarb, when applied as seed treatments, protected sorghum from damage at rates ⩾0.7 kg a.i./100 kg seed. These chemicals did not kill a high proportion of larvae, and feeding deterrence as the mode of action was indicated. The soil-active synthetic pyrethroids tefluthrin and bifenthrin, applied as banded sprays, protected seedlings and killed larvae at rates as low as 0.05 kg a.i. ha −1. The most effective organophosphate was ebufos, which protected seedlings at rates > 1.0 kg a.i. ha −1. In field trials on the Central Highlands of Queensland, seed treatments of carbofuran and furathiocarb significantly increased establishment of cotton and sorghum, but not that of sunflower, when false wireworm adults and wingless cockroaches ( Calolampra elegans Roth and Princis) were present. The carbamates were superior to pyrethroids in protection of emerging seedlings. Systemic insecticides did not prevent lethal damage to emerging sunflower seedlings when surface-active insect densities were similar to the numbers of seedlings (45 000 ha −1). Thiodicarb seed treatment in cotton (at 0.7 kg a.i./100 kg seed) significantly reduced numbers of black field earwig ( Nala lividipes Dufour).

Soil Insect Control in Sweet Corn, 1989

Abstract ‘Sundance’ sweet corn was planted 18 May at the Beef Unit, OARDC. Corn had been seeded in the plots after 1 Jun 1988, and no insecticide treatments were used that year. Plant spacing was 30 inches between rows. Plots consisted of 2 rows, 40 ft in length. Treatments were applied at planting with an electric Gandy applicator metering granular formulations in 7 inch bands or in the seed furrow. Band applications were placed in front of the press wheel and were immediately incorporated. Experimental design was a randomized complete block with 4 replications. Plots were inspected for signs of phytotoxicity after emergence and during the final evaluation. On 18 Jul, 4 root systems/plot were dug, washed, and rated according to the following scale: 1) no damage, 2) up to 2 roots pruned, 3) 3-6 roots pruned, 4) Vn of root mass pruned, 5) % root mass pruned, 6) all roots pruned.

Enhanced soil microbial degradation of capbofuran and fensulfothion - a factor contributing to the decline in effectiveness of some soil insect control programs in Canada

Abstract Compilation of field efficacy data accumulated over a number of years indicated that cabbage maggot (CM), Delia radicum (L.) control by carbofuran and fensulfothion in Newfoundland has declined with time. A similar trend was apparent in Ontario with carbofuran used to control carrot rust fly (CRF), Psila rosae (F.) and carrot weevil (CW), Listronotus oregonensis (LeConte). Laboratory tests conducted between 1982 and 1985 with 2 Newfoundland CM strains and an Ontario CRF strain indicated that declining efficacy could not be attributed to development of insect resistance to recommended insecticides. Other tests indicated that the 2 Newfoundland soils developed the capacity for rapid degradation of carbofuran or fensulfothion in a single growing season. In an organic soil used for carrot production in Ontario, anti‐carbofuran activity was apparent within 1 wk after application of granular carbofuran in the seed furrow and was high after 3 wk. The data suggest that development in soil of microbial populations capable of enhanced degradation of carbofuran or fensulfothion is contributing to the erratic performance of these insecticides in CM, CRF, CW and other root maggot control programs in Canada.

Soil Insect Control in Lupine, 1987

Abstract The trial was located on an irrigated sandy loam soil in the Irrigation Station, Staples, Minn. Plots were 2 rows × 25 ft, and treatments were replicated 4 times and arranged by pairs in a randomized complete block design. Clean, untreated seed was moistened with water and bacterial innoculant plus the appropriate insecticide applied 1 h prior to planting. The treated seed was then allowed to dry. Seed was planted with a John Deere Maximerge 4-row planter. Granular insecticides were applied by hand following planting and lightly covered. The field was then irrigated to provide uniform germination. Stand, insect, and disease damage were recorded for 20 ft of row. Damage was converted to a percentage, transformed using ARCSINE transformation, and means were compared. Yields were taken from 20 ft of row and adjusted to a standard moisture.

Bibliography of Imported Fire Ants and Their Control: Second Supplement

All the insecticides tested are registered for use on corn at or above the 1.12 kg Al/ha rate. In Louisiana, carbofuran has been the most frequently used insecticide for soil insect control in corn, terbufos and fensulfothion are also used. Based on the greenhouse experiments, growers should not expect sugarcane beetle control if carbofuran is used at planting. Isofenfos is no longer available for use on corn, therefore terbufos, fensulfothion or chlorpyrifos would be preferable if the sugarcane beetle is a recurrent problem. ACKNOWLEDGMENTS

Disappearance of Organochlorine Residues from Abdominal and Egg Fats of Chickens, Ontario, Canada, 1969-1982

Abdominal fats were collected from 8-week old broilers slaughtered at provincially inspected abattoirs across Ontario between 1969 and 1982. Domestically produced hen eggs were collected from either egg grading stations or producers over the same period. Composite samples were analyzed for organochlorine insecticides and industrial chemicals. Between 1979 and 1982, organophosphorus insecticides were routinely included in these analyses. Sigma DDT and PCB residues declined rapidly between 1969 and 1982 in extractable lipids of both abdominal and egg fats, while dieldrin declined less markedly over the same period. Declines in residues followed first order logarithmic regression equations. Chlordane and heptachlor epoxide were rarely observed above the detection limit of 1 microgram/kg in egg fat; however, the incidence of these residues in abdominal fat increased after 1973 following the removal of aldrin, dieldrin, and heptachlor in 1969 and the subsequent increased use of chlordane for soil insect control until 1977. Lindane residues were rarely observed above the detection limit. In 1979, when the detection limit was reduced, both alpha-BHC and lindane were identified, but at levels below 1 microgram/kg. Endosulfan, methoxychlor, and fenthion were identified on one or 2 occasions over the 13-year period.

Dieldrin, heptachlor, and chlordane residues in soybeans in Illinois 1974, 1980.

The Illinois soybean crop was monitored in 1974 and 1980 for dieldrin, heptachlor, and chlordane residues resulting from the use of these compounds for corn soil insect control in the years before extensive soybean cultivation. Residue levels were compared with past published amounts. Dieldrin residue levels in soybeans declined between 1974 and 1980. Heptachlor and heptachlor epoxide levels remained level between 1974 and 1980. Chlorinated hydrocarbon residues were lower in the southern third of Illinois than for the remainder of the state.

Organochlorine and Organophosphorus Residues in Fat of Bovine and Porcine Carcasses Marketed in Ontario, Canada from 1969 to 1981

Between 1969 and 1981, 2482 bovine and 554 porcine carcasses were sampled at provincially inspected abattoirs across Ontario. Abdominal fats were composited into 505 bovine and 122 porcine samples for analyses of organochlorine insecticides and industrial chemicals. Mean ∑DDT residues decreased from 257 μg/kg in 1969–70 to 12 μg/kg in 1981 for bovine fats and from 356 μg/kg in 1971–72 to 5 μg/kg in 1981 for porcine fats. Similar decreases in residue levels were observed for PCB. Dieldrin, with lower initial residues (i.e. 33 μg/kg in bovine fat and 12 μg/kg in porcine), decreased an order of magnitude over this same period. All decreases fitted first order logarithmic regression equations. Chloradane and heptachlor epoxide were rarely observed in bovine or porcine fat; however, the incidence in bovine fat increased after 1973 following the removal of aldrin, dieldrin and heptachlor in 1969 for soil insect control and the subsequent increased use of chlordane. Chlordane appeared at low levels (1–2 μg/kg) in bovine fat during the mid 1970s and remained detectable through 1981. Lindane residues in both bovine and porcine fat fluctuated from year to year and appeared to vary with the need to control insect pests. While present (2 to 39 μg/kg) in the early 1970s, lindane residues disappeared by mid 1970 but reappeared in fatty tissues in 1981 (3–13 μg/kg). A limited number of samples were analyzed for organophosphorus insecticides between 1973 and 1980 and residues were occasionally found. In 1981, the analyses became routine and 3.6% of bovine samples were found to contain detectable residues of fenthion; only 2 of 197 bovine samples exceeded the maximum residue levels permitted under the Food and Drug Act.