Laboratory evaluation of the effectiveness of the entomopathogen; Isaria farinosa, on citrus mealybug, Planococcus citri

Abstract

Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using four different inoculum densities and different relative humidities (RH). The entomopathogen caused 89.39% mortality in ovisacs, 84.07% mortality in second larval stage, 84.53% mortality in adult females, and 78.71% mortality in first larval stage at 95% RH and at 1 9 10 8 conidia ml -1 inoculum concentration. Percent mortalities were between 50 and 60 in ovisac, first and second larval stage at 95% RH and at 1 9 10 7 conidia ml -1 . Percent mortality was decreased parallel to the decrease in humidity level and inoculum densities; however, the fungus caused significant infection in 70% and 80% RH. These results demonstrated that the effectiveness of the entomopathogen is promising for biocontrol of citrus mealybug.

Laboratory evaluation of a new strain CCM 8367 ofIsaria fumosorosea(syn.Paecilomyces fumosoroseus) onSpodoptera littoralis(Boisd.)

“…The results obtained by El-Hawary and Abd El-Salam (2009), who used a higher concentration of 1 Â 10 9 spores/ml, realised mortality rates of 87.5, 72.5 and 67.5%, in 6.3, 8.2 and 7.4 days, respectively, using commercial products (Bio-Power (B. bassiana), Bio-Catch (L. lecanii) and Priority (P. fumosoroseus)) when tested on 3rd larval instars of S. littoralis. Similarly, Demirci et al (2011) stated that the entomopathogen I. farinosa achieved high pathogenic activity on the citrus mealybug, especially under humid conditions, and caused high mortality within six days of incubation. Also, Malarvannan et al (2010) found that the lowest pupation rate (43.33%) was observed in larvae treated with the highest spore concentration (2.4 Â 10 7 spores/ml) of B. bassiana and, additionally, that the resultant pupae had a higher chance of mortality and adult malformation.…”

Aislamiento, identificación y patogenicidad de Hirsutella en Planococcus citri.

“…Los porcentajes de patogenicidad de Hirsutella frente a la plaga al sexto día de haberse aplicado la solución conidiógena fueron altos (90%, 78,6% y 90,9%), con un promedio de 86,5% en comparación al control, que fue de 14,3%. Los porcentajes de mortalidad de 84,14% obtenidos por Demirci et al (2011b) con adultos de P. citri después de seis días de haber sido inoculados con el hongo entomopatógeno Isaria farinosa fueron similares al promedio obtenido en el presente estudio, lo que demuestra el efecto de las toxinas y enzimas que participan en la interrelación patógeno-hospedero según Rosas (2003).…”

“…Todos estos elementos afectan la calidad del fruto y disminuyen la capacidad fotosintética de la planta, lo que desencadena una reducción de su vigorosidad. (Demirci et al, 2011b).…”

“…La cochinilla transmite el Virus 3 Asociado al Enrollado de la Vid (GLRaV-3) (Demirci et al, 2011b) perteneciente al género Ampelovirus de la familia Closteroviridae, responsable de causar el enrollamiento hacia el envés en los viñedos (figura 1), así como enrojecimiento en variedades tintas. Además, es capaz de causar amarillamiento de las zonas internerviales (figura 2), mientras que en los racimos genera maduración heterogénea y menor contenido de azúcar (Vega et al, 2011).…”

Aspectos Biológicos de Espécies de Isaria (Persoon) após Infecção sobre Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

“…I. farinosa (Holm: Fries) Fries é citada na literatura como patogênica a várias espécies de insetos, como Pissodes punctatus Langor & Zhang, Planococus citri (Risso) e C. gestroi, entre outros (YANG et al, 2009;DEMIRCI et al, 2011;PASSOS et al, 2014). Isaria fumosorosea (Wize) Brown & Smith é isolada de uma variedade de insetos, sendo sua eficiência comprovada no controle de Plutella xylostella L., Coptorermes formosanus (Shiraki), Diaphorina citri Kuwayama, Panonychus ulmi (Koch), entre outros (XU et al, 2011;MEYLING;SCHMIDT;EILENBERG, 2012;WRIGHT;LAX, 2013;GRÄFF et al, 2017).…”