Efficacy and phytotoxicity of multiple petroleum oil sprays on sweet orange (Citrus sinensis (L.)) and pummelo (C. grandis (L.)) in Southern China

Abstract

Abs tract. The efficacy of pest control of three different oil formulations in multiple low-concentration spray programmes on sweet orange and pummelo were compared with unsprayed and normal farmer-treatments over three years. Phytotoxicity of sprays was assessed in terms of fruit and leaf drop, fruit yield and external fruit quality. Trees sprayed with any type of oil had lower pest numbers than unsprayed trees. On sweet orange, the heaviest oil was better than the normal farm practice at controlling chaff scale on fruit and red mite and whitefly on leaves. On pummelo it provided the best control of red mite on leaves. All three oils were as effective as the normal farm practice in control of rust mite on sweet orange fruit and leaves and red mite, rust mite and red scale on pummelo fruit. On sweet orange trees there was no evidence of phytotoxicity, and the external quality of fruit generally improved over time. On pummelo trees, oil sprays were unable to improve the external fruit quality. The number of pummelo per tree was reduced in three of the oil spray schedules in 1995 and one in 1996, but the total weight of fruit harvested per tree was unaffected.

Conservation of natural enemy fauna in citrus canopies by horticultural mineral oil: Comparison with effects of carbaryl and methidathion treatments for control of armored scales

“…Fortunately, it has been found that natural enemies of scale and some other pest insects are conserved if mineral oils are used (Walker & Aitken, 1996; Rae et al , 2000). Thus there is the opportunity to use IPM that combines biological control and intervention with mineral oils when necessary.…”

Pest management based on petroleum spray oil in navel orange orchard in Ganzhou, South China

“…This result suggested that PSO had no negative effect on the fruit quality and yield. Previous field studies (Rae et al 1996(Rae et al , 2000Huang et al 1998) also found no evidence of phytotoxicity caused by narrow range oil (C21, C23 and C27) on sweet orange trees. On the contrary, PSO could generally improve the external quality of fruit over time (Rae et al 2000).…”

“…With the development of optimized formulations, modern petroleum oils are more effective against pests and less phytotoxic than their predecessors. Studies in Australia (Beattie et al 1995a) and in China showed that the narrow-range oil did not cause any phytotoxicity to citrus trees (Rae et al 1996(Rae et al , 2000Huang et al 1998). Their use is advocated by the International Organic Agriculture Organization.…”

Costs and benefits of frequent low-volume applications of horticultural mineral oil for management of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

“…Petroleum-based horticultural mineral oils (HMOs) control citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), red scale, Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae), chaff scale, Parlatoria pergandii Comstock spiny whitefly, Aleurocanthus spiniferus (Quaintance) (Hemiptera: Aleyrodidae) and ACP in citrus Davidson, 1991;Rae et al, 1996Rae et al, , 1997Rae et al, , 2000. Most HMOs are relatively inexpensive, have low mammalian toxicity, little residual activity, and are relatively harmless to beneficial insects (Stansly et al, 2002).…”