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Simple Summary The solanum whitefly, Aleurothrixus trachoides, is a polyphagous pest known to attack > 70 crops worldwide. Endemic to the Neotropical region, in the past few years, it has emerged as a significant pest of several horticultural crops including pepper in the United States. To develop an eco-friendly sustainable management strategy for this pest, in this study, we evaluated the efficacy and compatibility of two commercially available biological control agents, predatory beetle Delphastus catalinae (Dc) and entomopathogenic fungi Cordyceps fumosorosea (Cfr) under laboratory conditions. Results showed both Cfr, treatments (alone or in combination with Dc) were efficacious, and Cfr did not negatively impact the beetle longevity. This study’s outcome is important not only for organic horticultural growers, but also for conventional growers as it offers a low-risk alternative tool for solanum whitefly integrated pest management in Florida and other affected regions. Abstract Aleurothrixus (formerly known as Aleurotrachelus) trachoides Back (Hemiptera: Aleyrodidae), commonly known as pepper or solanum whitefly, is a new emerging whitefly pest of several horticultural crops in the United States. During the preliminary survey for pepper whitefly infestation in Florida, a whitefly-specific predatory beetle Delphastus catalinae Horn (Coleoptera: Coccinellidae) was observed associated with this pest in the natural ecosystem. The current study was undertaken to determine the efficacy of this naturally occurring predator, D. catalinae, and an entomopathogenic fungus, Cordyceps (formerly known as Isaria) fumosorosea (Cfr) (Wize) (Hypocreales: Cordycipitaceae), alone or in combination, under controlled laboratory conditions. Whitefly mortality for Cfr (88%), beetle (100%) and Cfr + beetle (100%) treatments were similar and significantly higher compared to control. In the combination treatment, Cfr did not impact D. catalinae longevity and daily food intake, indicating a neutral interaction between the two treatments. Results showed that both of these natural biological control agents could potentially offer an effective alternative in the battle against invasive whiteflies such as pepper whitefly in U.S. horticulture production, either as a stand-alone strategy or in an integrated approach. Although these findings are promising, compatibility of the two treatments needs to be evaluated further under greenhouse and semi-field conditions before recommending to commercial growers.

The interactions between the entomopathogenic fungus Beauveria bassiana Balsamo (Vuillemin) (Hypocreales: Cordycipitaceae) and the entomopathogenic fungus Isaria fumosorosea (Wize) Brown and Smith (Hypocreales: Clavicipitaceae) were examined on young adults of Sitophilus granarius (L.) (Coleoptera: Curculionidae) and S. oryzae (L.) (Coleoptera: Curculionidae). Conidial suspensions of these entomopathogenic fungi were applied both separately and in combination, at three dosages, 104, 106, and 108 conidia/mL. Mortality of experimental adults was recorded daily for 15 days. An overall positive interaction between the pathogenic microorganisms was observed. Mean weevil mortality caused by the separate acting fungi, B. bassiana, ranged from 26.7% to 53.3% and from 36.6% to 63.3% for S. granarius and S. oryzae, respectively. The respective values for I. fumosorosea were 20.0%&ndash, 53.3% and 46.7%&ndash, 66.7%. The combined treatments showed a distinct interaction between the pathogens, for S. granarius, the interaction between the pathogens was additive in all combinations, whereas, for S. oryzae, the interaction was additive in seven and competitive in two of the combinations. Applying both entomopathogenic microorganisms may offer a method for weevil control that could be more effective than using each pathogen alone.

Entomopathogenic fungi are commonly applied as inundative sprays to protect plants against insect pests. Their artificial establishment as fungal endophytes to provide other benefits to the host plants aside mere protection against the primary pests has also been widely demonstrated. In the present study, two fungal strains of Beauveria bassiana and one strain of Isaria fumosorosea were assessed in a pathogenicity test against adults of Asian citrus psyllid (Diaphorina citri) and found to induce 50% reduction in the survival rate of D. citri adults within 5 days of exposure. The ability of the three fungal strains to endophytically colonize Citrus limon, the impact on plant growth and the effects of systemic colonization on 3 successive generations of D. citri feeding on colonized plants was evaluated. Citrus seedlings at 4 months post-planting were inoculated with each of the fungal strains via foliar spraying. Both strains of B. bassiana successfully colonized the seedlings. One of the B. bassiana strains (BB Fafu-13) was sustained up to 12 weeks in the colonized seedlings, whereas the other B. bassiana strain (BB Fafu-16) was only recovered up to 8 weeks post-inoculation. Isaria fumosorosea (IF Fafu-1) failed to colonize the plant. Both strains of B. bassiana induced significant improvement in plant height and flush production in endophytically colonized seedlings. In addition, endophytic B. bassiana caused 10&ndash, 15% D. citri adult mortality within 7 days of exposure. Female D. citri feeding on B. bassiana challenged plants laid fewer eggs as compared to those feeding on endophyte-free seedlings, while reduction in adult emergence was recorded on B. bassiana treated plants. With this study, we present the first evidence of B. bassiana artificial establishment as fungal endophyte in citrus plants and its negative effects on D. citri.

Biological control of the Mexican fruit fly, Anastrepha ludens, is mainly carried out by releasing parasitoids, such as Diachasmimorpha longicaudata, and by applying entomopathogenic fungi (EPF), such as Metarhizium anisopliae, Beauveria bassiana, or Isaria fumosorosea, which can be applied to the soil or dispersed using infective devices. The combined use of two or more biocontrol agents could improve A. ludens control, but IGP between natural enemies, if it occurs, may have negative effects. We evaluated the effects of EPF on D. longicaudata. First, we determined the susceptibility of adults of D. longicaudata to strains of EPF (Metarhizium robertsii strain V3-160 and M. anisopliae strain MAAP1). We also evaluated the infection of these two fungi on A. ludens larvae parasitized by D. longicaudata. Finally, we determined sub-lethal effects on adults of D. longicaudata that emerged from larvae that had been exposed to low concentrations of M. robertsii. Both fungi caused moderate mortality to D. longicaudata adults. There were no adverse effects on the longevity of parasitoids that emerged from parasitized larvae exposed to M. robertsii. Based on these results, we argue that M. robertsii has the potential to be used for biocontrol of A. ludens, with limited risk to D. longicaudata adults.

Laurel wilt is a disease threatening the avocado industry in Florida. The causative agent of the disease is a fungus vectored by ambrosia beetles that bore into the trees. Until recently, management strategies for the vectors of the laurel wilt fungus relied solely on chemical control and sanitation practices. Beneficial entomopathogenic fungi (EPF) are the most common and prevalent natural enemies of pathogen vectors. Laboratory experiments demonstrated that commercial strains of EPF can increase the mortality of the primary vector, Xyleborus glabratus, and potential alternative vectors, Xylosandrus crassiusculus, Xyleborus volvulus and Xyleborus bispinatus (Coleoptera: Curculionidae: Scolytinae). Our study provides baseline data for three formulated commercially-available entomopathogenic fungi used as potential biocontrol agents against X. crassiusculus, X. volvulus and X. bispinatus. The specific objectives were to determine: (1) the mean number of viable spores acquired per beetle species adult after being exposed to formulated fungal products containing different strains of EPF (Isaria fumosorosea, Metarhizium brunneum and Beauveria bassiana); and (2) the median and mean survival times using paper disk bioassays. Prior to being used in experiments, all fungal suspensions were adjusted to 2.4 × 106 viable spores/mL. The number of spores acquired by X. crassiusculus was significantly higher after exposure to B. bassiana, compared to the other fungal treatments. For X. volvulus, the numbers of spores acquired per beetle were significantly different amongst the different fungal treatments, and the sequence of spore acquisition rates on X. volvulus from highest to lowest was I. fumosorosea > M. brunneum > B. bassiana. After X. bispinatus beetles were exposed to the different suspensions, the rates of acquisition of spores per beetle amongst the different fungal treatments were similar. Survival estimates (data pooled across two tests) indicated an impact for each entomopathogenic fungus per beetle species after exposure to a filter paper disk treated at the same fungal suspension concentration. Kaplan–Meier analysis (censored at day 7) revealed that each beetle species survived significantly shorter in bioassays containing disks treated with EPF compared to water only. This study demonstrated that ambrosia beetles associated with the laurel wilt pathogen in avocados are susceptible to infection by EPF under laboratory conditions. However, the EPF needs to be tested under field conditions to confirm their efficacy against the beetles.

Horticultural oils are an important component of integrated management programs of several phytophagous arthropods and pathogens affecting fruit, ornamentals and vegetables in greenhouse and field production systems. Although effective against the target pest, their incompatibility with biological control agents can compromise efforts to develop eco-friendly management programs for important agricultural pests. In this study, we assessed the in vitro effect of selected refined petroleum oils used in citrus and other horticultural crops with a biopesticide containing the entomopathogenic fungi, Isaria fumosorosea (PFR-97) under laboratory conditions. Further, we used leaf disk bioassays to evaluate the combined efficacy of petroleum oils and I. fumosorosea against the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), a major pest of citrus in the United States. All five petroleum oil treatments (Orchex, Sun Pure, Conoco Blend -1, Conoco Blend -2, and JMS) were compatible with I. fumosorosea blastospores, as none of them were found to affect I. fumosorosea colony-forming units and radial fungal growth measured at 3, 6, 9, and 12 days post-inoculation. All mixed treatments performed better than I. fumosorosea alone against D. citri, where the highest mean survival time of D. citri was 12.5 ± 0.7 days. No significant differences in D. citri survival time and I. fumosorosea growth (fungal development index) on dead cadavers, which is important for determining their horizontal transmission, were observed when mixed with Orchex, Sun Pure, Conoco Blend -2, and JMS. Results indicated that horticultural oils in combination with I. fumosorosea could offer citrus growers an alternative treatment for integrating into their current management programs while battling against D. citri in citrus production systems. Due to their eco-friendly, broad-spectrum effect, it could provide control against various citrus pests, while also encouraging the retention of effective chemistries for a longer period in the marketplace. However promising, these combination treatments need to be tested further with I. fumosorosea under grove conditions to confirm their field efficacy.

The efficacy of topical, leaf residue, and soil drench applications with Isaria fumosorosea blastospores (Ifr strain 3581) was assessed for the management of the citrus root weevil, Diaprepes abbreviatus (L.). Blastospores of Ifr were applied topically at a rate of 107 blastospores mL−1 on both the larvae and adults, and each insect stage was incubated in rearing cups with artificial diet at 25 °C, either in the dark or in a growth chamber under a 16 h photophase for 2 weeks, respectively. Percent larval and adult mortality due to the infection of Ifr was assessed after 14 days as compared to untreated controls. Leaf residue assays were assessed by feeding the adults detached citrus leaves previously sprayed with Ifr (107 blastospores mL−1) in Petri dish chambers and then incubating them at 25 °C for 2–3 weeks. Efficacy of the soil drench applications was assessed on five larvae feeding on the roots of a Carrizo hybrid citrus seedling ~8.5–10.5 cm below the sterile sand surface in a single 16 cm × 15.5 cm pot inside a second pot lined with plastic mesh to prevent escapees. Drench treatments per pot consisted of 100 mL of Ifr suspension (107 blastospores mL−1), flushed with 400, 900, or 1400 mL of water compared to 500, 1000, and 1500 mL of water only for controls. The mean concentration of Ifr propagules as colony forming units per gram (CFUs g−1) that leached to different depths in the sand profile per treatment drench rate was also determined. Two weeks post-drenching of Ifr treatments, larvae were assessed for percent mortality, size differences, and effect of treatments in reducing feeding damage to the plant root biomass compared to the controls. Topical spray applications caused 13 and 19% mortality in larvae and adults after 7 days compared to none in the control after 14 days, respectively. Adults feeding on a single Ifr treated leaf for 24 h consumed less than the control, and resulted in 100% mortality 35 days post-treatment compared to 33% in the untreated control. Although offered fresh, untreated leaves after 24 h, only adults in the control group consumed them. Ifr CFUs g−1 were isolated 8.5–10.5 cm below the sand surface for the 1000 and 1500 mL drench rates only, resulting in 2%–4% larval mortality. For all the Ifr drench treatments, no differences were observed in percent larval mortality and size or the effect of treatments in reducing feeding damage to the plant root biomass compared to the controls. These results suggest that the foliar application of Ifr may be an efficient biocontrol strategy for managing adult populations of D. abbreviatus; potential alternative larval management strategies are discussed.

Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001) reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed.

(1) Global movement of propagative plant material is a major pathway for introduction of Bemisia tabaci (Hemiptera: Aleyrodidae) into poinsettia greenhouses. Starting a poinsettia crop with high pest numbers disrupts otherwise successful biological control programs and widespread resistance of B. tabaci against pesticides is limiting growers' options to control this pest; (2) This study investigated the use of several biopesticides (mineral oil, insecticidal soap, Beauveria bassiana, Isaria fumosorosea, Steinernema feltiae) and combinations of these products as immersion treatments (cutting dips) to control B. tabaci on poinsettia cuttings. In addition, phytotoxicity risks of these treatments on poinsettia cuttings, and effects of treatment residues on mortality of commercial whitefly parasitoids (Eretmocerus eremicus and Encarsia formosa) were determined; (3) Mineral oil (0.1% v/v) and insecticidal soap (0.5%) + B. bassiana (1.25 g/L) were the most effective treatments; only 31% and 29%, respectively, of the treated B. tabaci survived on infested poinsettia cuttings and B. tabaci populations were lowest in these treatments after eight weeks. Phytotoxicity risks of these treatments were acceptable, and dip residues had little effect on survival of either parasitoid, and are considered highly compatible; (4) Use of poinsettia cutting dips will allow growers to knock-down B. tabaci populations to a point where they can be managed successfully thereafter with existing biocontrol strategies.