Effect of Air Humidity on the Egg Viability of Predatory Mites (Acari: Phytoseiidae, Stigmaeidae) Common on Rubber Trees in Brazil

Abstract

Rubber pest mites, Calacarus heveae and Tenuipalpus heveae, reach economic damage levels at the end of the rainy season and the beginning of the dry season in Brazil. Therefore, low humidity adaptation might be an important characteristic for predatory mites to successfully control pest organisms. This study determined the effect of the relative humidity (RH) levels of 30-100% on the hatching of larvae of Amblyseius acalyphus, Euseius citrifolius, Iphiseiodes zuluagai, Metaseiulus camelliae, Agistemus floridanus and Zetzellia malvinae at 25 +/- 0.5 degrees C. These predatory mites are common on rubber trees in the state of São Paulo and might be used for introduction in the major rubber tree production regions in the state of Mato Grosso. At 70% RH or higher, viability was 70% or higher for all species, indicating that their performance might be higher during the rainy season than during the dry season. Eggs of E. citrifolius and M. camelliae presented higher viability at the lower relative humidity levels than those of other species, indicating that these species might have higher chance to persist in the dry season. It is suggested that M. camelliae should be further evaluated for introduction in the state of Mato Grosso, considering that this mite is not yet present in that area.

Biological parameters of Cydnodromus picanus and Phytoseiulus persimilis raised on the carmine spider mite, Tetranychus cinnabarinus (Acari: Phytoseiidae, Tetranychidae)

“…De Vis et al (2006) stated that Euseius citrifolius (Acari: Phytoseiidae) is a highly promising species for use as a biocontrol agent in arid environments. Our results with C. picanus allow us to point out that its performance in conditions of low RH could potentially surpass the performance of E. citrifolius, as C. picanus is a native species of desert environments that evolved in conditions of extreme aridity.…”

Life Table Parameters and Consumption Rate of Cydnodromus picanus Ragusa, Amblyseius graminis Chant, and Galendromus occidentalis (Nesbitt) on Avocado Red Mite Oligonychus yothersi (McGregor) (Acari: Phytoseiidae, Tetranychidae)

“…Using a data logger, the Petri dish micro-climatic conditions were registered inside the laboratory, thereby obtaining a temperature of 27 ± 1.93 ºC, relative humidity of 87 ± 3.61%, and a 16:8 (L:D) photoperiod for all the assays. These micro-climatic conditions were used to register the maximum biological potential of the predatory species since these are susceptible to low humidity in the egg stage (De Vis et al, 2006a). The experimental observations were carried out every 24 h with a 40X stereoscopical magnifying glass (Zeiss, Stemi, Göttingen, Germany).…”

Efecto de la humedad relativa en la viabilidad de huevos de Neoseiulus sp. y Proprioseiopsis iorgius (Acari: Phytoseiidae) en condiciones de laboratorio

“…como para P. iorgius y para cada humedad relativa (6,4%, 9,2%, 35,0%, 37,1% y 80,0%). Posteriormente, las placas se pusieron en el interior de una cámara de acrílico transparente, esta se selló con vaselina sólida para evitar la modificación de la humedad relativa (De Vis et al, 2006). Separadamente, se evaluaron las diferentes humedades (tratamientos): 6,4%, 9,2%, 35,0%, 37,1% y 80,0%.…”

“…Tello et al (2011) extienden su distribución hasta el litoral de la Región de Tarapacá (20º16'19,3" S,70º07'51,6" O). Diferentes factores afectan el éxito del control biológico con ácaros de la familia Phytoseiidae, entre los factores abióticos podemos citar la temperatura, la humedad relativa y pesticidas (De Vis et al, 2006;Hua et al, 2014) y dentro de los factores bióticos el canibalismo, la depredación intragremio, la escasez de alimento, la domatia, entre otros (Pozzebon et al, 2015;Ghasemlooa et al, 2016;Guo et al, 2016;Lv et al, 2016). Uno de estos factores, la humedad relativa, afecta directamente sobre la supervivencia de los huevos de los fitoseidos (Walzer et al, 2007;Ghazi y Amano, 2016).…”

“…Otro fitoseido muy tolerante a la baja humedad relativa es Typhlodromalus aripo De León, el cual registró un 70% de eclosión de sus larvas a 50% HR (17,8 hPa) y con una temperatura de 27 ºC (Mutisya et al, 2014). En Sudamérica, el fitoseido Euseius citrifolius Denmark & Muma ha demostrado una alta tolerancia de sus huevos a la baja humedad relativa, similar a Neoseiulus sp., registrando para 30 y 40% HR (22,2 y 19,0 hPa, respectivamente), porcentajes de eclosión de larvas de 30 ± 10% y 57 ± 7%, a una temperatura de 25 ºC (De Vis et al, 2006). Steiner et al (2003a) indican que alta humedad que requieren los huevos de T. lailae para eclosionar sugiere que esta especie podría ser utilizada en situaciones donde los huevos no estén sometidos a humedades extremadamente bajas y además la HR exceda el 70% durante varias horas en el día.…”