Effects of a Particle Film on Biology and Behavior of Diaphorina citri (Hemiptera: Psyllidae) and Its Infestations in Citrus

Abstract

Studies were conducted to investigate the effects of a kaolin-based hydrophilic particle film, Surround WP, on the biology and behavior of the psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) and to assess population densities of D. citri in citrus subjected to monthly applications of Surround WP. Laboratory investigations indicated a 3% (wt:vol) suspension of Surround WP in water applied directly was not acutely toxic to eggs, older nymphs or adults. Presence of the dried particle film on leaves interfered with the ability of adults to grasp and walk on citrus leaves. During a 30-s period, adults spent an average of 5 s moving on leaves with particle film compared with 16 s on leaves without particle film. When leaves were inverted, a significantly higher percentage of adults fell or flew from treated leaves (53%) than untreated leaves (16%). In a 12-mo study investigating infestations of D. citri on citrus treated monthly with Surround WP, cumulative reductions of 78% in adult numbers on mature leaves and of 60% in adult numbers on flush shoots (immature leaves) were observed in treated trees compared with untreated trees. Numbers of eggs and nymphs per flush shoot were reduced by 85 and 78%, respectively, in trees treated with particle film. Reductions in infestation levels of D. citri in treated trees were attributed to the negative effects of the particle film on the ability of adults to grasp, move, and oviposit. The suppressive effects of a Surround treatment against adult psyllids were degraded by rain.

Effects of processed kaolin on pests and non-target arthropods in a Spanish olive grove

“…Joubert et al (2004) found that Surround WP treatments caused mild repercussions for mango scale. For S. oleae, it is possible that a difficulty to grasp or move occurs, as has been reported for other insect species (Glenn et al 1999;Puterka et al 2005;Hall et al 2007); this difficulty may cause the insects to fall down and not find the right site for establishment.…”

“…Processed kaolin has been reported to effectively control different species of psyllids (Puterka et al 2000Glenn and Puterka 2005;Saour 2005;Hall et al 2007). However, in our study, Surround WP treatment did not have any effect on the numbers of E. olivina.…”

“…Also, it has no negative effect on human health or the environment; these characteristics as well as its mode of action not being prone to the development of resistance have resulted in the authorisation of its usage in organic agriculture (European Economic Community (EEC) 1991). From an economic point of view, which is a very relevant aspect for low input crops such as olive, processed kaolin could be less expensive than conventional insecticide treatments for controlling the olive fruit fly, as it has been seen in citrus for Diaphorina citri Kuwayama (Hall et al 2007).…”

Effects of kaolin particle films on the life span of an orb-weaver spider

“…According to Hall et al (2007) body size can be an important factor when assessing the effects of particle films on mortality among species. Considering body size of spider and fly, the former is considerably bigger than the latter, and this ratio spider/fly increases through the assay.…”

“…In this context, kaolin is a white aluminosilicate mineral clay, chemically inert over a wide pH range that has been widely used in a variety of industrial applications, including paints, cosmetics, pharmaceuticals and agriculture (Glenn et al, 1999;Glenn and Puterka, 2005;Knight et al, 2000). The interest for this natural substance is reflected in the number of works covering different crops such as pear Daniel et al, 2005), apple (Knight et al, 2001;Friedrich et al, 2003), olive (Pascual et al, 2010), walnut and almond (Rosati et al, 2006), citrus (Hall et al, 2007), wine grape (Glenn et al, 2010), pecan (Cottrell et al, 2002), cotton (Showler, 2003;Silva and Ramalho, 2012), tomatoes (Kahn and Damicone, 2008) and cabbage (Alavo and Abagli, 2011). In general, those and other studies showed kaolin as an effective substance in reducing the population of several groups of pests, such as Hemiptera (Daniel et al, 2005;Alavo and Abagli, 2011;Martinou et al, 2014), Lepidoptera (Showler, 2003;Sackett et al, 2007), Diptera (Mazor and Erez, 2004;Pascual et al, 2010) and Coleoptera (Silva and Ramalho, 2012).…”