Large numbers of different spotted larvae have recently been observed in many mungbean crops. The spotted larvae of the bean pod borer remains a significant pest of mungbeans yet the spotted fungus eating ladybird larvae poses no threat to crops. In recent years, significant populations of bean podborer larvae (Maruca vitrata) have been reported in crops as far west as… Read more »
An estimated 4,000 ha of soybeans near Casino in Northern NSW have been affected to varying degrees by soybean stem fly (Melanagromyza sojae) , a pest rarely seen in damaging numbers in Australia. Damage in many Casino crops is confounded by the presence of charcoal rot, a disease which blocks the plant’s vascular (xylem and phloem) tissue and causes similar… Read more »
Etiella (Etiella behrii) larvae have been observed in significant numbers (up to 10 larvae per square metre) in vegetative soybean crops in the Cecil Plains/ Pampas regions of the Darling Downs, and in low numbers (<1/sqm) in a DAFF soybean trial at Kingaroy. These infestations are likely due to the current hot and dry seasonal conditions which historically favour increased… Read more »
Calculating the economics of control is critical to making a decision about if and when Helicoverpa populations in chickpeas require treatment. This season, for the first time, growers and agronomists have access to an on-line calculator to help them make these decisions. The calculator overcomes the need to try and remember the formulas in the field. Best of all,… Read more »
Severe and sustained bean podborer (Maruca vitrata) outbreaks were widely reported in mungbeans over the past 2 summers.. Populations in excess of 100 larvae per square metre were observed in many crops. If left uncontrolled such populations not only impact on crop yield by reducing pod set, they also severely damage the pods that are set and delay harvest maturity…. Read more »
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 »
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 »
