Acaricide-impaired functional and numerical responses of the predatory mite, Amblyseius largoensis (Acari: Phytoseiidae) to the pest mite Raoiella indica (Acari: Tenuipalpidae)

The suppression of pest populations by a predator depends on two basic components of the predator-prey interaction: the functional and the numerical responses of the predator. Such responses can be affected by exposure to acaricides. In the present study, the effects of acaricides (abamectin, azadirachtin, fenpyroximate, and chlorfenapyr) on the functional and numerical responses of the predatory mite, Amblyseius largoensis (Acari: Phytoseiidae) an important natural enemy of the pest mite, Raoiella indica (Acari: Tenuipalpidae), were investigated. The exposure of A. largoensis to acaricides occurred through contact with a surface contaminated with dried acaricide residue. Subsequently, A. largoensis exhibited a type II functional response, which was not altered by exposure of any acaricides. However, exposure to abamectin resulted in a decrease in the average mean numbers of prey consumed by a predator. Exposure to acaricides increased prey handling time by 67%, 25%, 38%, and 35% for abamectin, azadirachtin, fenpyroximate, and chlorfenapyr, respectively. Exposure to abamectin reduced the attack rate of A. largoensis by 52%. The numerical response of A. largoensis was only affected by exposure to abamectin, where just 60% of the females oviposited, and regardless of the prey density, the average mean numbers of eggs/female/day was always less than 0.4. The food conversion efficiency into biomass of A. largoensis eggs decreased with increasing prey density, and this trend was not altered by exposure to any acaricides. However, exposure to abamectin drastically compromised the oviposition of A. largoensis, showing no increase in egg production with increasing prey density.

Carnaúba (Copernicia prunifera (Miller) H. E. Moore uma nova hospedeira de Raoiella indica Hirst (Acari: Tenuipalpidae)

The red palm mite, Raoiella indica Hirst, 1924 (Tenuipalpidae), has been spreading rapidly and expanding its host range in the Neotropical region. Most of the hosts are palm trees (Arecaceae). In the present work, high population levels of R. indica are reported on “carnauba” [Copernicia prunifera (Miller) H. E. Moore, Arecaceae] in the states of Alagoas and Ceará, northeastern Brazil. This is the first report of R. indica causing damage and injuries on this palm tree native to Brazil in field. Our results allow us to conclude that carnauba is a suitable host for R. indica, with potential risk to its cultivation and exploitation.

Predation capacity and larval development of Ceraeochrysa claveri (Neuroptera: Chrysopidae) fed with Raoiella indica (Acari: Tenuipalpidae)

Ceraeochrysa claveri Navás (Neuroptera: Chrysopidae) is a predator found in several agricultural ecosystems and feeds on insects and phytophagous mites. Its high reproductive potential and forage capacity makes it a candidate for biological control of agricultural pests. Raoiella indica Hirst (Acari: Tenuipalpidae) is an important pest that can damage several species of palms, in particular, Cocos nucifera L. Given the scarcity of available knowledge about the biological aspects of Chrysopidae fed with phytophagous mites, the present work aimed to study the larval development of C. claveri fed mainly with R. indica, in order to obtain information that would be of help in the integrated management of this pest. The evaluation was performed in the F0 generation. Larva 3 is the instar that consumes the most mites (F value = 32.99; P > 0.0001) (L3: 46.80 ± 10.12 a; L2: 9.80 ± 1.23 b; L1: 9.40 ± 1.58 b). C. claveri did not complete larval development when fed only with R. indica. Larval instars L1, L2 and L3 lived 7.4 ± 2.2, 7.6 ± 1.9 and 9.0 ± 3.9 days, respectively. The larvae that reached the pupal stage failed to grow further. When adding Sitotroga cerealella Olivier (Lepidoptera: Gelechidae) eggs to the diet, the development lasted 7.9 ± 0.2, 7.4 ± 0.8, 6.5 ± 0.9 and 13.6 ± 0.9 days for L1, L2, L3 and pupae, respectively. The adults lived on average 6.7 ± 4.9 days. The sexual ratio was rt = 0.42. According to the conditions under which the experiment was carried out, it can be inferred is that C. claveri cannot complete its development by feeding only on R. indica, and that it thus consumes this mite as an occasional prey. Highlights: Ceraeochrysa claveri is a predator found in various agricultural ecosystems and feeds on insects and phytophagous mites. Raoiella indica is an important mite that can damage several species of palms, in particular Cocos nucifera Ceraeochrysa claveri does not complete its biological cycle by feeding only on indica. By adding another protein source to L3, it can reach the adult stage in 35.4±2.8 days. Ceraeochrysa claveri does not complete its cycle by feeding only on R. indica and consequently takes this mite as occasional prey.

First report of damage and population dynamics of Raoiella indica Hirst (Acari: Tenuipalpidae) on Euterpe oleracea (Arecaceae) in the State of Bahia, Brazil

The presence of the red palm mite Raoiella indica Hirst, was recorded on açaí, Euterpe oleracea Mart. (Arecaceae), in Porto Seguro, Bahia State, northeastern Brazil. We evaluated the population dynamics of R. indica from September 2019 to February 2020. The population outbreak and most severe damage caused by R. indica was observed in February, a period of highest temperatures and low relative humidity. This is the first report of damage caused by the red palm mite on E. oleracea in Brazil. Management practices must be implemented to avoid intercropping açaí with other hosts of this mite e.g. coconut, banana and palm trees in order to minimize the occurrence and damage of R. indica on such agrosystems.

Raoiella indica (red palm mite).

R. indica was first described in India in 1924 (Hirst) and has since been reported in several Old World countries. The species became of recent significance in 2004 when it was first reported in the Caribbean (Flechtmann and Étienne, 2004). Since then the mite has successfully spread throughout the islands of the Caribbean and has expanded its range into southern Florida (USDA-APHIS, 2007), South America (northern Venezuela, Vásquez et al., 2008; Brazil, Navia et al., 2010; Colombia, Carrillo et al., 2011) and Mexico (Estrada-Venegas et al., 2010). The mite has been reported on a wide range of palm hosts of the family Arecaceae and apparent new associations with members of the order Zingiberales, including the families Musaceae, Heliconiaceae, Zingiberaceae and Strelitziaceae have been reported. The success of the mite in the invasive range may be attributed to its ability to colonize many different host plant species, its apparent lack of co-evolved natural enemies in its new habitat and its rapid dispersal in its new range.

Nuevos registros de plantas hospedantes de Raoiella indica Hirst en Colombia

Introducción. El ácaro rojo de las palmas Raoiella indica Hirst (Acari: Tenuipalpidae) se reconoce como una plaga cuarentenaria sobre hojas de palma de coco, desde 2004 en el continente americano. En Colombia su presencia se registró en 2010 y su dispersión por la costa atlántica ha sido rápida. Para el 2013 se reportó en los departamentos de Atlántico, Bolívar, Córdoba, Guajira, Magdalena, Norte de Santander y Sucre, en plantas de coco (Cocos nucifera), banano (Musa acuminata), heliconias y plátano (Musa paradisiaca). Objetivo. Conocer nuevas plantas hospedantes y la dispersión del ácaro R. indica en tres departamentos de Colombia. Materiales y métodos. Durante los años 2019 a 2020, en los departamentos colombianos del Meta (municipios de Villavicencio, Guamal, San Carlos de Guaroa y Granada), Casanare (municipio de Yopal) y Tolima (municipio del Guamo), se revisaron plantas de las familias Arecaceae, Musaceae y Heliconiaceae, que pudieran ser hospedantes del ácaro R. indica. Resultados. Se encontró que de los veinte taxones de plantas muestreadas, dieciséis son hospedantes de R. indica y de ellos uno constituye un nuevo hospedero. Se registró por primera vez la presencia de R. indica en los tres departamentos, principalmente en palmas de coco y varias plantas hospederas alternas que incluyen palmáceas, musáceas y Heliconia psittacorum. Conclusiones. El ácaro rojo R. indica se reportó por primera vez de manera oficial en los departamentos colombianos del Meta, Casanare y Tolima, y la palma de seje, Oenocarpus bataua Burret, se reporta como una nueva especie de planta hospedera para R. indica en Colombia.

Acaricidal activity of plant extracts against the red palm mite Raoiella indica (Acari: Tenuipalpidae)

The red palm mite Raoiella indica Hirst has recently invaded the Neotropical region, which demands the implementation of pest management strategies. In this study, toxicity of leaf extracts of Mexican oregano Lippia berlandieri Schauer, neem Azadirachta indica A. Juss, Mexican mint Plectranthus amboinicus (Lour.) Spreng., rue Ruta graveolens L. and Persian lime Citrus x latifolia Tanaka against R. indica was evaluated under laboratory conditions. Raoiella indica females were exposed to each plant extract at concentrations of 0.25, 0.50, 0.75 and 1% (v/v) to assess the cumulative mortality at 24, 48 and 72 h after exposure. Mortality rates of R. indica rose due to increased extract concentration and exposure time. The strongest acaricidal activity was observed with L. berlandieri, A. indica and P. amboinicus, whose 1% concentration and 72 h exposure caused a mean R. indica mortality of 100, 90 and 78%, respectively. These plant extracts hold promise for the chemical management of this pest