High soybean looper (Thysanoplusia orichalcea) populations (20-40/m2) have been reported in many regions in flowering and podding soybeans. While soybeans can tolerate 33% defoliation with no yield loss during the vegetative stages, their defoliation tolerance slips to 16% during podset/early podfill. Consequently, consider taking action if high looper populations are threatening your crop. Large soybean looper (38 mm). Note the tapered… Read more »
Damaging bean podborer (Maruca vitrata) populations of up to 100+ larvae/m2 have been observed in flowering and podding mungbeans in the South Burnett, Dawson Callide and Central Highlands. Although podborer is not an uncommon pest in these regions during wet summers, very high populations can inflict devastating damage with zero pod set observed in some crops where the pest is… Read more »
As the cotton season draws to a close it is time to for the DAFF team working on Silverleaf whitefly (SLW) resistance monitoring to start making collections of whitefly from across the cotton-growing regions. Even if SLW numbers are below threshold, it is possible for the team to make collections of either nymphs (on leaves) or adults (using the suction… Read more »
Management of whitefly this season will be challenging as a result of the high rainfall and flooding in November and again in February which has resulted in a wide spread of crop maturity both between and within each region. While some cotton crops will mature on time, others could be set back by as much as six weeks by the cool… Read more »
There have been several reports of GVB occurring in late cotton crops. This has led to some confusion in the industry as to whether GVB needs to be controlled at this late stage in cotton. Research done by DEEDI entomologists has shown that younger bolls are more susceptible to lint damage caused by GVB feeding. These factors need to be… Read more »
Broad mites have shown up in cotton crops in Emerald and in the Gwydir this season. Whilst the mites themselves are extremely small and difficult to see, even with a handlens, being familiar with symptoms of broad mite infestation may assist with a diagnosis.
Noticeable numbers of grass blue butterfly larvae (Zizina labradus) have been observed in young soybean crops in the Wide Bay Burnett. While the small green larvae (maximum length 10 mm) may be difficult to see in the crops, the damage they cause is very obvious. Grass blue butterfly larvae feeding results in windowing of the leaves (this is mostly cosmetic)… Read more »
There have been several reports of high numbers of apple dimpling bug (ADB) in early squaring cotton throughout the major cotton growing valleys. Also known as the yellow mirid, ADB adults (about 3mm long) are about one third the size of green mirid adults. They are yellow-green, have dark spines on the legs and hairy wings that are folded flat on… Read more »
As the earlier plantings of sorghum progress through flowering, moderate to high Helicoverpa pressure means that many crops have caterpillar numbers over threshold. Nucleopolyhedrovirus (NPV) is one of the main insecticides used to control Helicoverpa larvae in sorghum, however prevailing conditions play an important role in the speed and level of control achieved with NPV.
As the cotton season gets underway aphids are starting to be detected in crops, on ratoons, volunteers and weeds. Last season, there were some regions where Cotton Bunchy Top (CBT) was detected in crops towards the end of the season. To assess and manage the risk of yield loss caused by CBT, and minimise the difficulties of controlling insecticide resistant… Read more »
