Search

Insecticidal treatment options based on putative integrated pest management (IPM) compatible active ingredients spirotetramat, sulfoxaflor and buprofezin were evaluated for efficacy against first and second instar (small) and large (third instar and adult) cotton mealybugs, Phenacoccus solenopsis. Four field evaluations were conducted at the Department of Agriculture and Fisheries (Queensland) research station facilities at Kingaroy (KRS) and Emerald (ERS) in 2016 and 2017. Two ‘insecticide evaluations’ included treatment options with different rates of active ingredients and adjuvants, aimed at validating efficacy results obtained in previous glasshouse evaluations. The other two ‘IPM evaluations’ were designed to test the compatibility of selected insecticidal active ingredients with naturally occurring beneficial arthropods through differential exclusion by means of large field cages configured to be either partially open or fully closed to regulate access. Spirotetramat gave consistent and commercially acceptable (≥80%) control of large and small mealybugs at the highest rate of 96 g in these insecticide evaluations. The addition of crop oil to spirotetramat as a tank mix partner significantly enhanced efficacy, as documented previously in glasshouse evaluations. Sulfoxaflor provided equivalent control of large and small mealybugs but only at the ERS site. The overall control efficacy of buprofezin was equivalent to spirotetramat and sulfoxaflor at the ERS site but inferior to both at the KRS site. In the IPM evaluations, the abundance of predatory arthropods and their potential contribution to overall mortality was generally low. Parasitism contributed significantly to overall mortality among treatments over time and was independent of cage status (closed or open). Large mealybugs were equitably distributed between the upper (terminal) and lower sections of the cotton plant canopy in both ERS evaluations whereas in the KRS evaluations the distribution

The efficacy of commercially available chemical insecticides and biopesticides on the cotton mealybug (CMB), Phenacoccus solenopsis, was evaluated in the glasshouse. Spirotetramat, sulfoxaflor and buprofezin were identified as key insecticides for use in integrated pest management (IPM) strategies aimed at controlling CMB without flaring other co-occurring pests. When used as a single application, spirotetramat and sulfoxaflor at the rate of 96 g (active ingredient, ha−1) provided variable control of CMB. Spirotetramat used in a double spray tactic (two sequential sprays, 14–15 days apart) without crop oil provided ≥80% control of adult CMB while the addition of oil (5% v/v) increased control to ≥90%. Clothianidin synergised the spirotetramat + oil combination and was identified as a potentially useful tank mix option for use in situations where a quick knockdown of high density and/or large infestation of CMB is required, or to treat high risk infestations in squaring or younger cotton when the abundance of beneficial insects is typically low. Sulfoxaflor used in a double spray tactic provided ≥90% control of adult CMB. The addition of Pulse® penetrant (0.5% v/v) to both options improved overall efficacy. Addition of crop oil to sulfoxaflor did not yield any tangible benefits. Spirotetramat and buprofezin were identified as important tools in managing situations where whitefly (Bemisia tabaci) is the primary pest management target, but CMB is also present in the crop. Buprofezin was effective on early instar mealybugs; this makes it an option for arresting CMB population growth while allowing the beneficial insect populations to increase. Sulfoxaflor was shown to be a useful option in situations where CMB is present along with key pests such as mirids (Creontiades spp.). Mealybugs are typically well controlled by naturally occurring beneficial insects without the need for insecticide use. Chemical insecticides for CMB control should be considered only as a

The solenopsis mealybug (Phenacoccus solenopsis) is widespread throughout QLD and in 2017 was confirmed as being present in the cotton growing areas in the Gwydir and Namoi valleys of northern NSW. Solenopsis mealybug adults are 3-4 mm long and have two characteristic dark longitudinal bare spots across their thorax and abdomen (look like black spots). Solenopsis is a high priority pest for the cotton industry for several reasons: (i) it causes direct yield loss, plant damage and death, typically in the form of patches or dead plants or ‘hot spots’ (ii) populations of solenopsis are easily flared by spray practices targeting other pests such as mirids and mites which require frequent control in Bollgard III cotton production systems; (iii) it is very easily dispersed by wind and rain, and through the movement of infested plants, farm machinery, vehicles and on clothing and footwear; (iv) it’s population dynamics are highly unpredictable. Weed and volunteer plant control, farm hygiene practices and the conservation of naturally occurring beneficial insects (lacewings, Cryptolaemus, 3-banded ladybird, Aenasius wasp) are key elements of successful solenopsis mealybugs control in cotton. Research done over the last three years by the Queensland Department of Agriculture and Fisheries staff in Toowoomba and Emerald has resulted in the identification of sulfoxaflor, buprofezin and spirotetramat, new generation, IPM-compatible insecticidal compounds with efficacy on solenopsis mealybugs. Spray Oils were also identified as having a significant suppressive effect. The cotton industry is currently working with registrants towards permit/registrations.

This project includes research on three pests, mirids, stinkbugs and solenopsis mealybug. The project objectives are listed below: 1. Investigate solenopsis mealybug damage in Bollgard II cotton 2. Explore management options for mealybug 3. Develop improved monitoring techniques for mirids (sample size vs precision) 4. Determine temperature effects on mirid feeding 5. Investigate IPM-compatible management options for mirids and stinkbugs 6. Investigate cotton stainer damage in Bollgard II (develop threshold) 7. Investigate causal agents of boll rot and potential links with bug transmitted pathogens

The Cotton Catchment Communities Cooperative Research Centre began during a period of rapid uptake of Bollgard II® cotton, which contains genes to express two Bt proteins that control the primary pests of cotton in Australia, Helicoverpa armigera and H. punctigera. The dramatic uptake of this technology presumably resulted in strong selection pressure for resistance in Helicoverpa spp. against the Bt proteins. The discovery of higher than expected levels of resistance in both species against one of the proteins in Bollgard II® cotton (Cry2Ab) led to significant re-evaluation of the resistance management plan developed for this technology, which was a core area of research for the Cotton CRC. The uptake of Bollgard II® cotton also led to a substantial decline in pesticide applications against Helicoverpa spp. (from 10–14 to 0–3 applications per season). The low spray environment allowed some pests not controlled by the Bt proteins to emerge as more significant pests, especially sucking species such as Creontiades dilutus and Nezara viridula. A range of other minor pests have also sporadically arisen as problems. Lack of knowledge and experience with these pests created uncertainty and encouraged insecticide use, which threatened to undermine the gains made with Bollgard II® cotton. Here we chronicle the achievements of the Cotton CRC in providing the industry with new knowledge and management strategies for these pests.

Here we review the current knowledge of green mirids, Creontiades dilutus (Hemiptera: Miridae). Creontiades dilutus are highly polyphagous pests that are endemic to Australia. They are widely distributed across Australia and feed on a broad range of agricultural crops. Recently, C. dilutus has become an important focus of pest control in Australian cotton crops, most likely due to a decrease in insecticide use associated with the widespread uptake of transgenic cotton varieties. Prior to this, C. dilutus had been coincidentally controlled in cotton by applications of insecticides targeted at other pests such as Helicoverpa spp. Further, the pest status of C. dilutus in summer pulse crops has become more apparent due to the increased research dedicated to this area over the past decade. We review various aspects of the biology and ecology of C. dilutus, including their life cycle, feeding behaviour and host plants. We also examine current control methods and laboratory-rearing techniques, which will be important for the development of novel control strategies in cotton and other cropping environments. Possible future research directions are highlighted, such as dispersal capabilities and extent of genetic structure within C. dilutus populations, as these will have important implications for effective and sustainable control in the future.

In recent years mirids and stinkbugs have emerged as important sucking pests in cotton. While stinkbugs are causing damage to bolls, mirids are causing damage to seedlings, squares and bolls. With the increasing adoption of Bollgard II and IPM approaches the use of broad-spectrum chemicals to kill Helicoverpa has been reduced and as a result mirids and stinkbugs are building to levels causing damage to bolls later in crop growth stages. Studies on stinkbugs by Dr Moazzem Khan revealed that green vegetable bug (GVB) caused significant boll damage and yield loss. A preliminary study by Dr Khan on mirids revealed that high mirid numbers at later growth stages also caused significant boll damage and that damage caused by mirids and GVB were similar. Mirids and stinkbugs therefore demand greater attention in order to minimise losses caused by these pests and to develop IPM strategies against these pests to enhance gains in IPM that have been made with Bt-transgenic cotton. Progress in this area of research will maintain sustainability and profitability of the Australian cotton industry. Mirid damage at early growth stages of cotton (up to squaring stage) has been studied in detail by Dr Khan. He found that all ages of mirids cause damage to young plants and damage by mirid nymphs is cumulative. Maximum damage occurs when the insect reaches the 4th and 5th nymphal stages. He also found that mirid feeding causes shedding of small and medium squares, and damaged large squares develop as ‘parrot beak’ bolls. Detailed studies at the boll stage, such as which stage of mirids is most damaging or which age boll is most vulnerable to feeding, is lacking. This information is a prerequisite to developing an IPM strategy for the pest in later crop growth stages. Understanding population change of the pest over time in relation to crop development is an important aspect for developing management strategies for the pest which is lacking for mirids in BollgardII. Predators and parasit