The entomopathogenic nematode Steinernema kraussei and Metarhizium anisopliae work synergistically in controlling overwintering larvae of the black vine weevil,Otiorhynchus sulcatus,in strawberry growbags

Previously, the combination of reduced rate of entomopathogenic nematodes (EPN) and fungus caused additive or synergistic mortality to third-instar black vine weevil (BVW), Otiorhynchus sulcatus. In this study, we examined this interaction in unheated glasshouses during winter and compared a combination of commercial formulation of a cold-tolerant EPN, S. kraussei (Nemasys L?) and fungus Metarhizium anisopliae strain V275 against overwintering third-instar BVW. The combination of M. anisopliae with S. kraussei at a rate of 1×10¹⁰ conidia+250,000 nematodes/growbag resulted in additive or synergistic effects, providing 100% control of overwintering larvae.     

Biological control of the black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) with entomopathogenic nematodes (Nematoda: Rhabditida)

Trials conducted under glasshouse conditions showed that control of Otiorhynchus sulcatus larvae in strawberry plants can be effective using Steinernema carpocapsae and Heterorhabditis megidis, given that temperature and moisture extremes are avoided. In field experiments, the double line T-Tape® drip irrigation system performed better than the single line T-Tape® system, effectively distributing the nematodes along and across strawberry raised beds, and placing them close to the root zone where O. sulcatus larvae feed. As soil temperatures are satisfactory for nematode infectivity from late spring to early autumn, nematode applications were aimed at late instar larvae during spring, and early instar larvae during summer. Late summer field treatment with S. carpocapsae induced 49.5% reduction of the early instar larvae, and field application of the same nematode species in late spring resulted in 65% control of late instar larvae. In the same trial, spring application of H. megidis caused 26% mortality of late instar larvae of O. sulcatus.     

Control of Black Vine Weevil larvae Otiorhynchus sulcatus (Fabricius) (Coleoptera:Curculionidae) in grow bags outdoors with nematodes

Abstract 1 Outdoor trials were carried out during 2001–02 on strawberries grown in commercial growing bags naturally infested with black vine weevil larvae (BVW) Otiorhynchus sulcatus in Co. Wexford, Ireland. 2 The two nematode isolates used in these trials were Heterorhabditis megidis (UK211) and Heterorhabditis downesi (K122), both laboratory cultured. Growing bags received nematodes either once (May 2001), twice (May and October 2001) or three times (May, October 2001 and May 2002). Ten days after each application date, nine blocks (of the total 27) were randomly selected, destructively assessed and discarded. 3 The single application (May 2001) resulted in a mortality of black vine weevil larvae, of 93.4% with H. megidis and 51.3% with H. downesi, compared with the control treatment at that date. Respective figures after the double application (May 2001 and October 2001) were 78.9 and 77.6% and after the triple application (May 2001, October 2001 and May 2002) the figures were 93.7 and 88.1%. 4 Results from these trials clearly indicate that entomopathogenic nematodes are good alternatives to chemical control of the black vine weevil on strawberries grown in growing bags in Ireland.     

Sustainable control of black vine weevil larvae,Otiorhynchus sulcatus (Coleoptera: Curculionidae) with Heterorhabditis bacteriophora in strawberry

Efficacy, persistence and recovery of the nematode Heterorhabditis bacteriophora was tested in the laboratory after application of the nematode to strawberry roots by dipping. To mitigate nematode sedimentation and improve attachment to strawberry roots, carboxy-methyl-cellulose was added to the nematode solution. Mortality of black vine weevil Otiorhynchus sulcatus varied between 90 and 96% in the pot trials.     

A review of the biology and control of the vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae)

At the turn of the century, damage by Otiorhynchus sulcatus was sporadic and limited to small areas. Increasing horticultural intensification and the adoption of husbandry techniques favourable to the weevil, such as the use of polythene mulches, increased its pest status. The development of the early inorganic pesticides reduced the number of serious outbreaks of this pest and weevil control was further improved by the development of the persistent organochlorine insecticides in the 1940's. The banning of a number of the more persistent insecticides over recent years has now left the horticultural industry in a very vulnerable position. O. sulcatus is now a pest on a range of horticultural crops throughout the temperate regions of the world. Infestations are most common in Europe (where it originated) and the USA, and nearly 150 plants species have been identified as potential hosts to O. sulcatus. Damage is most frequently caused by the root feeding larval stage. Populations as low as one larva plant can kill sensitive species such as Cyclamen. Severe damage by the leaf feeding adults is less common, although low levels of damage or contamination by adults may be unacceptable in certain situations. There is one generation a year. Oviposition by the flightless parthenogenetic females occurs over the summer months with oviposition rates of c. 500 and 1200 eggs adult^-1for outdoor and laboratory populations, respectively. O. sulcatus mainly overwinters as larvae, although significant numbers of adults may survive in areas where winter temperatures are not too severe. A number of natural enemies, such as hedgehogs, frogs and predatory beetles, help to maintain O. sulcatus populations at a low level in natural environments, but they are less successful in intensive horticultural systems where persistent chemicals have been heavily relied on to maintain the population below the economic threshold level. Increasing environmental concern is now forcing growers to consider new pest control strategies. Controlled release formulations of non-persistent products, such as fonofos and chlorpyrifos, have shown potential as control agents for O. sulcatus larvae. Biological control agents, such as insect parasitic nematodes, have been developed commercially and new microbial control agents are in the process of development. Most of the new control products are directed towards control of O. sulcatus larvae. Adult vine weevils are nocturnal and a much more difficult target for the new control agents. It is likely that an integrated approach to pest control will be required to maintain O. sulcatus populations below their economic threshold level.     

Efficacy and persistence of entomopathogenic nematodes for black cutworm control in turfgrass

Field experiments were conducted in turf maintained under golf course fairway conditions in May, June, and August 2009 and in August and September 2010 to evaluate the ability of entomopathogenic nematodes to control larval populations of the black cutworm, Agrotis ipsilon, on golf courses. Commercial products containing the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae, S. feltiae, and S. riobrave were applied at 1.0 or 2.5×10⁹ infective juveniles per ha against fourth-instar black cutworms. Larval mortality and turf damage were evaluated at 4 and/or 7 days after treatment (DAT). Steinernema carpocapsae was the best performing species due to a combination of high control rates (average 83%), most consistent results (70–90% range), high speed of kill (average 68% at 4 DAT), and prevention of significant turf damage despite very high larval densities at 0 DAT. Efficacy of S. feltiae and H. bacteriophora was often similar to that of S. carpocapsae but overall less consistent. Short-term persistence of the nematodes was evaluated in four turfgrass sites maintained under golf course putting green, fairway, or rough conditions in June and August 2009 by baiting soil samples at 0, 4, 7, and 14 DAT. Relative to recovery immediately after application, at least 50% of S. feltiae and 25% of S. carpocapsae consistently persisted up to 4 days in one of the greens and up to 7 days in some trials. Our finding suggests that S. carpocapsae and S. feltiae may provide adequate black cutworm control in golf course turf under moderate summer temperatures.     

The influence of temperature on the susceptibility of vine weevil, Otiorhynchus sulcatus (Fabricius) (Coleoptera: Curculionidae), larvae to Metarhizium anisopliae (Deuteromycotina: Hyphomycetes)

Mortality of Otiorhynchus sulcatus (Fabricius) larvae at 10^oC, 15^oC, 20^oC and 25^oC following treatment with 10⁷conidia ml“¹suspensions of six Metarhizium anisopliae (Metschnikoff) Sorokin isolates was temperature dependent. In all cases, the LT₅₀s were inversely related to temperature, but the nature of this response varied between isolates. Strain 101-82 was the most virulent isolate at 25^oC with an LT₅₀ of 3.7 days, but it was the least virulent isolate at 15^oC and it failed to kill any O. sulcatus larvae at 10^oC. In contrast, strain 159-83 had the lowest virulence at both 20^oC and 25^oC, whereas it was the most virulent isolate at 10^oC with an LT₅₀ of 20.0 days. The mortality rates followed a similar pattern and were positively related to temperature in all cases with the exception of strain 159-83 at 25^oC. Mycosis development was examined on larvae treated with strain 275-86 and significant differences were obtained between all four temperatures. Sporulation commenced after approximately 2.75 days at 25^oC, but took nearly 11 days at 10^oC. The infection rates also varied between temperatures; sporulation occurred on 98% of the treated larvae at 25^oC, but only on 93%, 87% and 49% of the larvae at 20^oC, 15^oC and 10^oC, respectively. The results of these bioassays demonstrate that temperature has a significant effect on the virulence of M. anisopliae. The differences between fungal strains also emphasises the importance of selecting isolates for specific situations on the basis of their temperature profiles.     

The effect of the CpTi gene in strawberry against attack by vine weevil (Otiorhynchus sulcatus F. Coleoptera: Curculionidae)

The degree of protection against insect feeding conferred upon transgenic strawberry lines expressing the Cowpea trypsin inhibitor was evaluated under glasshouse conditions. Insect bioassays were carried out using vine weevil (Otiorhynchus sulcatus) in two experiments and in both experiments there was a highly significant reduction in damage by weevil larvae on the transgenic lines.     

Combined use of entomopathogenic nematodes and Metarhizium anisopliae as a new approach for black vine weevil,Otiorhynchus sulcatus,control

Combined use of the entomopathogenic nematodes (EPNs), Heterorhabditis bacteriophora Poinar (Heterorhabditidae), Steinernema feltiae Bovien, and Steinernema kraussei Steiner (Steinernematidae) and the insect‐pathogenic fungus, Metarhizium anisopliae (Metsch.) Sorokin (Clavicipitaceae) was evaluated for control of third‐instar black vine weevil, Otiorhynchus sulcatus Fabricius (Coleoptera: Curculionidae). Black vine weevil larvae were exposed to various concentrations of M. anisopliae and EPNs and mortality was assessed weekly or at 3‐day intervals under laboratory and greenhouse conditions. The EPNs were added simultaneously, or 1 or 2 weeks after application of M. anisopliae. Throughout the experiments, the combined application of EPNs with M. anisopliae resulted in increased efficacy against black vine weevil. When the EPNs were applied 1 or 2 weeks after application of the fungus, 100% larval mortality was obtained, even when the biocontrol agents were used at reduced rates. The interactions observed suggest that EPN and M. anisopliae work together synergistically in potted Euonymus fortunei Blondy (Celastraceae) under greenhouse conditions and may provide a powerful and economically feasible approach for black vine weevil larval control.     

Susceptibility of the boll weevil to Steinernema riobrave and other entomopathogenic nematodes

The susceptibility of the boll weevil (BW), Anthonomus grandis Boheman, to Steinernema riobrave and other nematode species in petri dishes, soil (Hidalgo sandy clay loam), and cotton bolls and squares was investigated. Third instar weevils were susceptible to entomopathogenic nematode (EN) species and strains in petri dish bioassays at 30 degrees C. Lower LC(50)'s occurred with S. riobrave TX- 355 (2 nematodes per weevil), S. glaseri NC (3), Heterorhabditis indicus HOM-1 (5), and H. bacteriophora HbL (7) than H. bacteriophora IN (13), S. riobrave TX (14), and H. bacteriophora HP88 (21). When infective juveniles (IJs) of S. riobrave were applied to weevils on filter paper at 25 degrees C, the LC(50) of S. riobrave TX for first, second, and third instars, pupae, and 1-day-old and 10-days-old adult weevils were 4, 5, 4, 12, 13, and 11IJs per weevil, respectively. The mean time to death, from lowest to highest concentration, for the first instar (2.07 and 1.27days) and second instar (2.55 and 1.39days) weevils were faster than older weevil stages. But, at concentrations of 50 and 100IJs/weevil, the mean time to death for the third instar, pupa and adult weevils were similar (1.84 and 2.67days). One hundred percent weevil mortality (all weevil stages) occurred 3days after exposure to 100IJs per weevil. Invasion efficiency rankings for nematode concentration were inconsistent and changed with weevil stage from 15 to 100% when weevils were exposed to 100 and 1IJs/weevil, respectively. However, there was a consistent relationship between male:female nematode sex ratio (1:1.6) and nematode concentration in all infected weevil stages. Nematode production per weevil cadaver increased with increased nematode concentrations. The overall mean yield of nematodes per weevil was 7680IJs. In potted soil experiments (30 degrees C), nematode concentration and soil moisture greatly influenced the nematode efficacy. At the most effective concentrations of 200,000 and 400,000IJs/m(2) in buried bolls or squares, higher insect mortalities resulted in pots with 20% soil moisture either in bolls (94 and 97% parasitism) or squares (92 and 100% parasitism) than those of 10% soil moisture in bolls (44 and 58% parasitism) or squares (0 and 13% parasitism). Similar results were obtained when nematodes were sprayed on the bolls and squares on the soil surface. This paper presents the first data on the efficacy of S. riobrave against the boll weevil, establishes the potential of EN to control the BW inside abscised squares and bolls that lay on the ground or buried in the soil.     

Efficacy of entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) against codling moth,Cydia pomonella (Lepidoptera: Tortricidae) in temperate regions

The biocontrol potential of South African isolates of Heterorhabditis zealandica, Steinernema citrae, S. khoisanae, S. yirgalemense, and Steinernema sp., was evaluated against codling moth, Cydia pomonella. Codling moth was susceptible to all six nematode isolates at a concentration of 50 infective juveniles/insect (78–100% mortality). Low temperatures (10 h at 17°C; 14 h at 12°C) negatively affected larvicidal activity (≤3%) for all isolates. All tested isolates were most effective at higher levels of water activity (a _w=1). The average a _w50-values for all isolates tested was 0.94 (0.93–0.95), except S. khoisanae 0.97 (0.97–0.98). Regarding host-seeking ability, no positive attraction to host cues could be detected amongst isolates, except for H. zealandica. Three of the isolates, H. zealandica, S. khoisanae, and the undescribed Steinernema sp., were selected for field-testing and proven to be effective (mortality >50%). Insect containment methods used during field experimentation was shown to influence larvacidal activity, as different levels of mortality were obtained using various containment methods (wooden planks vs. pear tree logs vs. mesh cages). Pear tree logs were impractical. Predictive equations were subsequently developed, enabling future trials to be conducted using either planks or cages, enabling the prediction of the expected level of control on tree logs. All tested isolates therefore showed a certain degree of biological control potential, however, none of the experiments showed clear efficacy-differences amongst isolates. The study highlighted the importance of environmental factors to ensure the successful application of these nematodes for the control of diapausing codling moth larvae in temperate regions.     

Effect of soil type on infectivity and persistence of the entomopathogenic nematodes Steinernema scarabaei, Steinernema glaseri, Heterorhabditis zealandica, and Heterorhabditis bacteriophora

We tested the effect of soil type on the performance of the entomopathogenic pathogenic nematodes Steinernema scarabaei, Steinernema glaseri, Heterorhabditis zealandica, and Heterorhabditis bacteriophora. Soil types used were loamy sand, sandy loam, loam, silt loam, clay loam, acidic sand, and a highly organic potting mix. Infectivity was tested by exposing third-instar Anomala orientalis or Popillia japonica to nematodes in laboratory and greenhouse experiments and determining nematode establishment in the larvae and larval mortality. Infectivity of H. bacteriophora and H. zealandica was the highest in potting mix, did not differ among loamy sand and the loams, and was the lowest in acidic sand. Infectivity of S. glaseri was significantly lower in acidic sand than in loamy sand in a laboratory experiment but not in a greenhouse experiment, and did not differ among the other soils. Infectivity of S. scarabaei was lower in silt loam and clay loam than in loamy sand in a greenhouse experiment but not in a laboratory experiment, but was the lowest in acidic sand and potting mix. Persistence was determined in laboratory experiments by baiting nematode-inoculated soil with Galleria mellonella larvae. Persistence of both Heterorhabditis spp. and S. glaseri was the shortest in potting mix and showed no clear differences among the other substrates. Persistence of S. scarabaei was high in all substrates and its recovery declined significantly over time only in clay loam. In conclusion, generalizations on nematode performance in different soil types have to be done carefully as the effect of soil parameters including soil texture, pH, and organic matter may vary with nematode species.     

Selection responses and quantitative-genetic analysis of preadult performance on two host plants in the bean weevil, Acanthoscelides obtectus

The infectivity and biocontrol potential of entomopathogenic nematodes against two common urban tree leaf beetles (Altica quercetorum and Agelastica alni) pupating in the soil were examined under laboratory and semi‐field conditions. In the laboratory experiments, pre‐pupae and pupae of both insect species were shown to be highly susceptible to nematode infection when challenged in soil pre‐treated with the parasites’ infective juveniles. In general, Heterorhabditis megidis was more effective than Steinernema feltiae. However, significant differences were observed between individual isolates within the latter species. Nematodes developed and reproduced in cadavers of both insect species. A semi‐field experiment studying the biocontrol potential of selected nematode strains, conducted under the canopy of urban trees, confirmed the preliminary laboratory findings and revealed that H. megidis could eliminate most of the insects pupating in the soil, when applied at a relatively low dose of 10⁵ IJs m^?2. The potential of entomopathogenic nematodes as environmentally safe, effective, and economically viable agents for the biological control of tree leaf beetles in urban green areas is discussed.     

Effectiveness of entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora on the Colorado potato beetle Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) under laboratory and greenhouse conditions

In laboratory and greenhouse studies, the invading ability, virulence, and mortality caused by Stinernema feltiae and Heterorhabditis bacteriophora were compared. After one and two days of exposure to either nematode species, the mortality of Colordo potato beetle (CPB) Leptinotarsa decemlineata larvae at different instars, third and fourth, was recorded and the number of nematodes invading cadavers was more than the number of nematodes inside the larvae at the late last instar (one day before pre-pupa). Two concentrations, 250 and 500 IJs/dish, infective juvenile nematodes/0.5 ml were tested on different CPB larval instar. S. feltiae was more effective, with fourth instar rather than third and late last instar. On the other hand, H. bacteriophora showed a very weak effect with L. decemlineata. Also it was clear that S. feltiae was more effective and faster than H. bacteriophora: more than 70% of larvae were killed within 24 hours compared with H. bacteriophora which killed 40% of larvae within 48–72 hours. A significant difference in invading efficiency was observed with concentration 2500 IJs/pot in the greenhouse test. The number of adult females found in the cadavers of L. decemlineata larvae was always higher than the number of males. Foliage application of S. feltiae and H. bacteriophora resulted in a significant reduction of the number of damaged leaves and a lower index of damage compared with that in the control. We conclude that S. feltiae has significant potential and can help in the management of the Colorado potato beetle.     

Efficacy of two entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae for control of the leopard moth borer Zeuzera pyrina (Lepidoptera: Cossidae) larvae under laboratory conditions

The biological traits of the entomopathogenic nematodes (EPNs), Steinernema carpocapsae and Heterorhabditis bacteriophora, against the larvae of the leopard moth, Zeuzera pyrina were evaluated in the laboratory. The traits included pathogenicity, penetration potential as well as foraging behaviour. Plate assays were performed using a range of EPN concentrations (5, 10, 20, 50 and 100 infective juveniles (IJs) per larva). The LC₅₀ values for S. carpocapsae and H. bacteriophora were 6.4 and 8.4 IJs larva^?1 after 72 h. Both EPN species caused high mortality in branch experiments. Significantly higher mortality rates occurred in the larger larvae after exposure to S. carpocapsae. Both EPN species successfully penetrated the Z. pyrina larvae as well as larvae of Galleria mellonella L. (Lepidoptera: Galleridae).The proportional response of H. bacteriophora to host-associated cues was strongly higher than S. carpocapsae in Petri dishes containing agar 1, 12 and 24 h after EPN application. These results highlight the efficiency of EPNs for the control of Z. pyrina larvae. However, due to the cryptic habitat of Z. pyrina larvae in their galleries in the trees, field trails need to be conducted to further evaluate this potential.     

Natural enemies of natural enemies: the potential top‐down impact of predators on entomopathogenic nematode populations

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Effect of potting media on the efficacy and dispersal of entomopathogenic nematodes for the control of black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae)

The effect of five commercial potting media, peat, bark, coir, and peat blended with 10% and 20% compost green waste (CGW) on the virulence of six commercially available entomopathogenic nematodes (EPN), Heterorhabditis bacteriophora UWS1, Heterorhabditis megidis, Heterorhabditis downesi, Steinernema feltiae, Steinernema carpocapsae, and Steinernema kraussei was tested against third-instar black vine weevil (BVW), Otiorhynchus sulcatus. Media type was shown to significantly affect EPN virulence. Heterorhabditis species caused 100% larval mortality in all media whereas Steinernema species caused 100% larval mortality only in the peat blended with 20% CGW. A later experiment investigated the effect of potting media on the virulence of EPN species against BVW by comparing the vertical dispersal of EPN in the presence and absence of BVW larva. Media type significantly influenced EPN dispersal. Dispersal of H. bacteriophora was higher than H. megidis, H. downesi, or S. kraussei in all media, whereas, S. feltiae and S. carpocapsae dispersal was much reduced and restricted to peat blended with 20% CGW and coir, respectively. In the absence of larvae, most of the EPN species remained in the same segment they were applied in, suggesting that the larvae responded to host volatile cues. Greenhouse trials were conducted to evaluate the efficacy of most virulent strain, H. bacteriophora in conditions more representative of those in the field, using 2.5 × 10⁹ infective juveniles/ha. The efficacy of H. bacteriophora UWS1 against third-instar BVW was 100% in peat, and peat blended with 10% and 20% CGW but only 70% in bark and coir, 2 weeks after application. These studies suggest that potting media significantly affects the efficacy and dispersal of EPN for BVW control.     

Effectiveness of Steinernema spp. and Heterorhabditis bacteriophora against Popillia japonica in the Azores

Steinernema carpocapsae (Breton strain), S. glaseri, and Heterorhabditis bacteriophora were evaluated for their potential to control immature stages of the Japanese beetle, Popillia japonica, on Terceira Island (the Azores). In bioassays carried out at temperatures higher than 15 C, S. glaseri and H. bacteriophora caused 100% mortality of larvae, whereas S. carpocapsae caused 56% larval mortality. At temperatures slightly below 15 C, only S. glaseri remained effective. In field plots, in September, S. glaseri and S. carpocapsae reduced larval populations by 91% and 44%, respectively, when applied at the rate of 10⁶ nematodes/m². In April, S. glaseri caused 31% reduction in numbers of larvae, but S. carpocapsae was ineffective. In colder months (November-February) neither steinernematids nor H. bacteriophora reduced larval populations. Increasing the application rate from 10⁶ to 5 x 10⁶ infective stage S. glaseri per m² increased efficacy from 63% to 79% mortality.     

Combination of the fungus Beauveria bassiana and pheromone in an attract‐and‐kill strategy against the banana weevil,Cosmopolites sordidus

An attract‐and‐kill approach based on pellets from soybean or palm stearin fats blended with the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. sensu lato and the aggregation pheromone sordidin (Cosmolure^®) was tested against the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae). The viability of B. bassiana conidia, blended with hydrogenated oil and exposed for up to 150 min to heating at 50 °C, was not affected and the aggregation pheromone did not undergo any decomposition. Conidial viability in pellets decreased by 50% after an average of 15.1 and 9.1 days at 25 and 40 °C, respectively, when packaged in polypropylene bags. Active packaging (hermetic bag + O₂/moisture‐absorbing sachet) increased the shelf lives almost 10 and 6 times at 25 and 40 °C, respectively. In olfactometer bioassays, fat pellets amended with pheromone (sordidin, 1% wt/vol) were highly attractive to C. sordidus adults for up to 15 days, after which the pheromone release rate had decreased by about 90% and pellets were no longer attractive. Pellets with pheromone and conidia were as attractive to C. sordidus as banana rhizomes, and considerably more attractive than pieces of pseudostem. In no‐choice experiments conducted in boxes, survival of insects exposed to fungus‐impregnated pellets was affected by fat type (soybean fat vs. palm stearin) and bioassay temperature (25 vs. 30 °C), with results favoring soybean fat pellets at the higher temperature (96.9% of mortality after 18 days and ST₅₀ of 7.7 days). However, mortality levels were low (21.7% for soybean fat pellets) or very low (1–5% for palm stearin pellets) in choice experiments carried out at 25 °C when fungus‐impregnated pellets were applied before or after exposure of pseudostem residues to insects, respectively. The potential of this delivery system to manage C. sordidus populations and other insect pests (including those with cryptic habits) is discussed.