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 »
Two spotted mites (TSM) or red spider mites have been reported in damaging numbers in many mungbean crops on the Darling Downs and in Northern NSW. Crops at particular risk are those adjacent to maturing cotton (or any other mite hosts) from which mites are dispersing in large numbers. As TSM are very small (0.5 mm) the first evidence of their… Read more »
With some chickpea crops being sprayed out, rather than harvested, there are reports of helicoverpa larvae surviving on crop residues. The survival of larvae, particularly large late instar larvae, poses a threat to subsequent crops that may be sown directly into the chickpea residues. It is important to check for surviving larvae under the chickpea residues before the next crop… Read more »
While soybeans are more likely to be attacked by helicoverpa from flowering onwards, severe infestations can occur as early as the seedling stage. In recent years, severe early infestations have been reported on the Downs and in the coastal Burnett with the affected crops experiencing significant yield losses. The latest published thresholds for helicoverpa in vegetative soybeans (Rogers and Brier,… Read more »
With the approach of spring, helicoverpa start to become active. In CQ, chickpea crops are attractive to moths, and it is timely to revisit some of the key points related to making decisions about control of this pest in crops.In this article, I wanted to discuss a couple of the recommendations which some growers and agronomists have found a bit… 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… Read more »
Go soft early Go soft early is a basic integrated pest management (IPM) strategy to avoid using non selective pesticides for as long as possible. This approach encourages a build up of predators and parasites to keep early pests in check and buffer the crop against attack later in the season. This strategy is particularly important in soybeans because of… Read more »
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… Read more »
Revised thresholds for helicoverpa in flowering/podding mungbeans are based on a rate of damage of 35 kg/ha per larva per square metre in podding crops. The new thresholds are nearly double the old threshold of 1/m2, and make allowances for variations in control costs and crop value. For a typical scenario with pesticide control (including aerial application) costing $40/ha and… Read more »
