Leafhoppers (also known as jassids) rarely cause damage in cotton, so some unusual symptoms (leaf chlorosis that presented a little like cotton bunchy top disease) across several cotton fields in Queensland’s Burnett region last month that appeared to be associated with leafhoppers had both taxonomists and virologists searching for an explanation. Both the damage and leafhoppers present shared many of… Read more »
Late damage has been reported recently in an Onyx-AU (PBR*) black gram crop in the Burdekin. The most obvious damage was dead leaves, but closer inspection found full sized larvae (3 mm) and pupae in the petioles of damaged leaves. The causal agent was common bean fly Ophiomyia phaseoli (Agromyzidae), but in this instance control was not warranted, as the… Read more »
Halo blight, caused by a bacterial pathogen (Pseudomonas savastanoi pv. phaseolicola) is one of the major diseases of beans world-wide, particularly in temperate regions. In mungbean, symptoms on leaves start as small, water-soaked lesions that are surrounded by a yellow-green halo (Figs 1 and 2). Symptoms may be visible at the 1st or 2nd trifoliate leaf stage and are often… Read more »
Since early 2020, growers and agronomists have been nervous about the prospect of fall armyworm (FAW; Spodoptera frugiperda) invading their crops. So far, the majority of significant and damaging FAW infestations have been recorded from sweet corn, maize, and sorghum crops, with some isolated outbreaks in horticultural crops such as ginger and capsicum. Occurrences in other crops have been a… Read more »
As we enter the business end of the season, we want our soybean crop’s leaves to be a healthy green, as the healthier the leaves, the more the pods fill and the higher the yield. In a drought year, dryland crops turn brown prematurely due to lack of water, but in wet years or in irrigated crops, leaves should not… Read more »
Fall armyworm (FAW) are still active across the Northern Grains Region, but inland Central and Southern Queensland have not experienced continuous population build up in crops since the first immigration of moths in September–October. One of the major contributors to this continuing low pressure is probably the very high natural enemy (beneficial) impact on FAW. A number of very common… Read more »
Another exotic leaf-mining fly, the serpentine leafminer (SLM; Liriomyza huidobrensis), also known as pea leafminer or South American leafminer, has recently been found in commercial vegetable crops (celery and green beans) in the Fassifern Valley (90 km south-west of Brisbane). This follows its previous detection in western Sydney in early November. The national plant pest and disease incursions technical committee… Read more »
Helicoverpa outbreaks in wheat are relatively rare events. The last big outbreak, in 2016, was the first significant event for several decades, so treating helicoverpa in wheat is not something that many agronomists are familiar with. However, 2020 looks to be a year when helicoverpa infestations in some crops may warrant control. Wet winters are well correlated with outbreaks of… Read more »
Termites are common in undisturbed parts of the landscape, playing an important role in the ecosystem. It is unusual to find them in crops—but in 2020, there have been several reports of termites in winter cereals. The first reports were received during crop establishment, and more were received once the crops started to come out in head and set grain…. Read more »
Key points: There was a resurgence in tobacco streak virus (TSV) disease in mungbeans in early 2020 TSV is restricted to central QLD and closely related to the distribution of parthenium weed Growers are encouraged to avoid areas of dense parthenium to reduce risk In autumn of 2020, tobacco streak virus (TSV) was found to be common in all mungbean… Read more »