The Solenopsis Mealy bug pages will be subject to change as more information becomes available.
Page Publication Date: Wednesday, 10 March 2010
Since December last year, growers from west of Emerald have reported the presence of mealybug in some cotton fields and from mid January reports have indicated that this was becoming more serious. As a result of this, the cotton industry bodies (CRC, CRDC and CA), along with DEEDI and Biosecurity Qld have formed an Industry working group and have initiated a range of actions to protect the cotton industry.
The mealybug was identified as being an exotic (imported) pest. This species, Phenacoccus solenopsis, was also identified in Texas in 1990. In Pakistan and India in it was identified in 2004 and has caused significant economic loss within those cotton industries. However, since then, this species has succumbed to a large degree of predation by a range of native predators including lacewings and ladybirds and, in particular in India and Pakistan, an accidentally introduced parasitic wasp.
The Cotton CRC funded a survey to be undertaken in the Emerald region to determine the extent of the infestation, the amount of damage and also to identify any factors which could be associated with presence or absence of infestations which might provide indicators to assisting the management of this threat. The initial survey covered 27 of the 28 farms west of Emerald and 25 of the 27 farms assessed had some degree of mealy bug presence. However, the majority of fields of cotton were free of mealybug.
Of the approximately 80 fields affected, 25 have a significant presence and only around 6 fields have a significant crop loss. The net loss is not great overall, and this is mainly concentrated in just 2 or 3 farms. Early indications appear to indicate that certain factors may predispose areas of cotton to be more susceptible to infestation. These factors may include the presence of ratoon cotton over the fallow period; weedy drains/fields (especially pigweed, sesbania, parthenium and bladder ketmia); stressed areas of cotton (either waterlogged/soak areas; dry areas such as shallow, sandy or duplex areas within clay fields, or nutrient stressed areas); multiple in-crop ground operations (which can spread mealy bug throughout the field) and destruction of predators through pesticide usage. However, these factors still require the presence of mealy bug to provide the first populations.
Mealy bug can travel by air currents (the small crawler stage); irrigation and tail water and by contaminated vehicles, animals and personnel entering the field. Although little can be done to prevent spread by the former two methods, we can guard against infestation through control of vehicular and personnel movement within and between fields. Having said this, knowledge of wind direction, areas perennially subject to stress conditions and those areas adjacent to possible sources of mealybug can be useful in planning how best to concentrate monitoring efforts on farm. The earlier an infestation can be identified, the easier it will be to control without having to resort to destructive pesticide usage.
Cotton CRC is setting up a site on the insect identification section of the where the most up[ to date Industry information and protocols will be posted as they are available. You are now in this site.
