Selection and characterization of Beauveria spp. isolates to control the broad mite Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae)

Abstract

This study was performed under laboratory conditions to identify isolates of the fungus Beauveria spp. that can control Polyphagotarsonemus latus in the greenhouse and field. Thirty Beauveria spp. isolates were tested by spraying 1 mL conidia (1 × 10 8 conidia/mL) on pepper leaf discs containing 15 mites. Evaluations were performed on the 3rd and 6th day post application by counting the number of dead mites. Vegetative growth and conidial production were measured from the selected isolates, and bioassays were conducted in the greenhouse on bean seedlings in plastic pots. The isolate Unioeste 53 was selected, and a conidial suspension (1 × 10 8 conidia/mL) was applied with a backpack sprayer. The evaluation consisted of pre-and post-treatment counts of the number of live mites on ten leaflets in both the plots treated with the fungus and control plots, and the same procedure was followed for the field experiment. In the laboratory, the Unioeste 53 isolate resulted in total and confirmed mortality rates of 70% and 57.7%, respectively. In the greenhouse, the population decreased by 76.71% by the 16th day after application. In the field, the population decreased by 66% by the 12th day after application, demonstrating the potential of this fungus for mite management.Keywords: microbial control, entomopathogenic fungi, broad mite. Seleção e caracterização de isolados do fungo ResumoEste trabalho teve por objetivo selecionar isolados do fungo Beauveria bassiana em condições de laboratório com potencial de uso em casa de vegetação e campo no controle do ácaro branco. Foi realizada uma seleção com 30 isolados de Beauveria spp. através de pulverização direta de conídios (1 × 10 8 conídios/mL) sobre discos foliares de pimenta contendo 15 ácaros. As avaliações foram realizadas no terceiro e sexto dia contando-se o número de mortos, e confirmação do patógeno em câmara úmida. Parâmetros de crescimento vegetativo e produção de conídios foram avaliados. No bioensaio em casa de vegetação foram preparados vasos com plantas de feijão e fez-se a aplicação do Unioeste 53 (1 × 10 8 conídios/mL), utilizando pulverizador costal, a avaliação constou da contagem prévia e posterior à aplicação do número de ácaros vivos em 10 folíolos, tanto nas parcelas destinadas ao tratamento com fungo, quanto na testemunha. A fase de campo seguiu os mesmos padrões, porém, com área experimental total de 225 m 2 , com oito parcelas de 10,24 m 2 , sendo 4 testemunhas e 4 onde foi aplicado o isolado Unioeste 53 seguindo metodologia de aplicação e avaliação já descritas para casa de vegetação. Em laboratório o isolado Unioeste 53 causou mortalidade total de 70% e 57,7% de mortalidade confirmada. Em casa de vegetação, apresentou redução da população de 76,71% 16 dias após aplicação, já em campo, a redução da população foi de 66% após 12 dias da aplicação, demonstrando o potencial do ácaro pelo fungo.Palavras-chave: controle microbiano, fungos entomopatogênicos, ácaro branco.

Ekspresi morfologi tiga jenis jeruk sebagai indikator ketahanan terhadap serangan Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae)

“…Spons dilapisi dengan tisu yang dibasahi, selanjutnya daun jeruk diletakkan di atas kapas dengan permukaan abaksial menghadap atas. Kemudian daun dilapisi dengan tisu yang sudah dilubangi pada bagian daun (Martins et al 2016). Untuk mencegah kekeringan pada spons dan menjaga kondisi daun dalam keadaan turgid, dilakukan penyiraman dua hari sekali pada cawan petri (Puspitarini et al 2021a).…”

“…Pada tanaman yang terinfestasi, TPJ sebagian besar memakan bagian apikal tanaman (Rosado et al 2014) dan memecahkan dinding sel tanaman dengan chelicerae-nya (Jeppson et al 1975;Zhang 2003), yang mengakibatkan kebocoran konten intraseluler (Martins et al 2016). Perubahan morfofisiologis tanaman yang disebabkan oleh TPJ akan menyebabkan terhambatnya pertumbuhan tanaman, bunga dan buah rontok, juga penolakan oleh konsumen karena kerusakan, seperti distorsi daun, perubahan warna bunga, dan buah melepuh (Gerson 1992;Grinberg et al 2005;Sarmento et al 2011).…”

Evaluation of indigenous fungal entomopathogens and aqueous leaf extract of Annona muricata against Polyphagotarsonemus latus infesting Jatropha curcas in Indonesia

“…To make an arena, a water-soaked sponge (5 cm x 5 cm x 1.5 cm) was placed inside a Petri dish (d = 9 cm). The sponge was covered with moistened cotton, and then, a citrus leaf was placed over the cotton with the abaxial surface facing up (Martins et al 2016). Regular watering was done to maintain the humidity in Petri dishes, keep the leaf in turgid condition, and prevent the desiccation of the mites (Puspitarini et al 2021).…”

“…Thereafter, mites that emerged on the same day were taken for the experiment. Following the treatments, mortality was checked daily during 6 days of the observation period (Martins et al 2016). Test mites were assumed dead if there was no movement of the appendages when being touched with a brush.…”

Effects of Water Activity and Temperature on Entomopathogenic Fungal Culture, Implications on Conidia Integrity and Virulence

“…A major consideration in the development of entomopathogenic fungi for biological control is the selection of the most virulent strains against the target pest [5]. Abadias et al [6] suggested that, for a fungal biocontrol agent to be suitable for use under field conditions, it is important that the inoculum has necessary ecological fitness to withstand abiotic interactions in form of natural fluctuations in temperature and relative humidity.…”