The Resistance Roadshow visited regional areas during late August and presented the latest resistance monitoring results for a suite of important pests. Presentations covered resistance to conventional insecticides in cotton aphids, mites, silverleaf whitefly and helicoverpa, and helicoverpa resistance to the Bt toxins in Bollgard II. Read More
The most critical issues we face in managing cereal aphids currently is the lack of local knowledge about the likely impact of infestations on yield and quality (the damage thresholds). (http://thebeatsheet-ipmnews.blogspot.com/2008/09/cereal-aphids-in-wheat-and-barley.html). Read More
Slaters are not generally regarded as a pest of broad acre agriculture and tend to feed on decaying vegetation and dead animal matter. Overall they perform an important recycling role in the environment however on rare occasions they can also attack seedlings of broad acre crops. Read More
Detection of Q biotype Bemisia tabaci in Australia
The presence of Q biotype Bemisia tabaci species complex in Australia has been confirmed by Dr Robin Gunning, NSW DPI. Q biotype was collected from vegetables in the Bowen/Burdekin region during late 2008, as well as from cotton in southern Queensland (Goondiwindi) and north-western NSW (Wee Waa) during 2009. It is likely that Q biotype is more widely distributed than just these regions. Read More
Field crickets
High numbers of field crickets have been reported across the Darling Downs in the last couple of weeks, with some large aggregations of adults attracted to lights at night. Are these crickets doing damage to crops? The answer may well be yes.
Mirids can cause significant crop losses in mungbeans with yield reductions of up to 25-50% common where high mirid populations (eg 10/m2) are left uncontrolled. Mirids can reduce yields by 60 kg/ha for every mirid/m2 of crop.
Mirids can be present in mungbeans at any stage from seedlings to podding. Budding, flowering and early-podding crops are at greatest risk. Low populations of green mirids are often present in vegetative crops but there is no evidence they cause ‘tipping’ of vegetative terminals or have any impact on yield. Mirid populations usually increase with the onset of budding and peak during late podfilll. Generally around 80% of mirids present in flowering/podding crops are nymphs.. Read More
Green Vegetable Bugs (GVB) in soybeans 
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Soybean moth Aproaerema simplexella is a very common pest of soybeans but is usually only present in very low numbers. This season high numbers of moths and caterpillars were found especially in the Wide Bay Burnett region with some fields sustaining extensive damage. Similar leaf miners attack many horticultural crops, but are species other than A. simplexella. Weed hosts of soybean moth include emu foot (Psoralia tenax)
Identification
The soybean moth is a small narrow winged moth, up to 6 mm long. The forewings are dark brown/grey, each with a white bar across them, and pale brown hind wings. In soybean crops with large infestations, moths can be seen flying up from the foliage when disturbed.
Soybean moth infestations are favoured by hot, dry weather, with crops under severe moisture stress most at risk. Large populations can cause extensive damage by stripping all leaves from crops and so reduce photosynthesis and grain production.
The indicative threshold is based on defoliation, with. 33% pre flowering and 15-20% defoliation during early to mid pod-fill.
Control
In most years control is not required but large infestations in the Bundaberg region will need chemical control to prevent total crop loss. Check thoroughly before spraying, as larvae may have already pupated (as black pupae within the webbing) or reached full size (7 mm) and stopped feeding.
There are no specific registrations for the control of soybean moth. However pesticides effective against Helicoverpa (except Helicoverpa virus and Bt), and targeting that pest in soybeans will most likely also give reasonable control of soybean moth.
Other caterpillars that mine and web soybean leaves include soybean leafminer Lithocolletis aglaozona, a much smaller and less abundant species, and legume webspinner Omiodes diemenalis, common in coastal regions, but which is much larger (up to 15 mm) and is bright green. Legume webspinners also web leaves together, rather than mining leaves (feeding inside them).
Similar leaf miners also attack many horticultural crops, but are species other than A. simplexella. Weed hosts of soybean moth include emu foot (Psoralia tenax).
Damage
Larvae initially feed inside leaves (i.e. in leaf mines) and emerge after approximately four days to feed externally, folding and webbing leaves together to form a protective shelter. Infested leaves are often crinkled and pulled together in the middle and this together with webbing of leaf is the most obvious symptom of damage. In low numbers the larvae only cause cosmetic damage. While larvae normally feed on leaves only, extremely high populations will also graze on the surface of pods, after they have denuded the crop of leaves.
Bad Behavior has blocked 88 access attempts in the last 7 days.
Recce for armyworm in winter cereals
The quick finish for winter cereals this season has resulted in the majority of crops escaping infestations of armyworm. Headers are already into some fields, but there are reports of armyworm making their presence felt in some of the later crops. Read More »