se rating. Lush growth or lodging that provides a humid microclimate under the crop canopy enhances the inherent variety susceptibility. PBA Jumbo2, PBA Herald XT and the supersede variety Nipper are rated resistant (R) to botrytis grey mould. Several others are rated moderately susceptible to moderately resistant (MS/MR). Other lentil varieties are moderately susceptible (MS) to BGM, but PBA Bolt and Northfield are particularly susceptible (S).
Do not grow lentil in, or adjacent to, paddocks where grey mould has recently infected chickpea or lentil, or where chocolate spot has infected faba bean.
See also 'Lentil: Integrated disease management'
Lentil crops surveyed in South Australia and Victoria commonly have Cucumber Mosaic Virus (CMV) present, a disease that can occasionally express as a major problem. Viruses do pose a threat to lentils if ignored. In unique cases where lentil crops have experienced heavy losses from viral infection, it has been in association with prolonged, high levels of aphids that arrived early. Combinations of CMV, Alfalfa Mosaic Virus (AMV) and Beet Western Yellows Virus (BWYV) are often present when lentil crops are sampled.
The most important factors that predispose pulse crops to severe virus infection are:
- close proximity to a substantial virus reservoir (e.g. lucerne, summer weeds, infected lentil seed)
- high summer-autumn rainfall and the subsequent uncontrolled multiplication of aphids on host plants.
Early aphid flights to newly emerged crops can cause economic loss as early infection has a larger impact on yield and infected plants will act as a inoculum source for further virus spread within the crop.
Lentil problem solver
- 'Lentil: Integrated disease management'
- ‘Virus management in pulses’
- Crop protection products for current permits and registrations for pulses
- Refer to individual product labels and local professional advice.
Redlegged earth mite (RLEM) (Halotydeus destructor) and blue oat mite (BOM) (Penthaleus major) can cause significant damage to young lentil crops. Mite-damaged leaves have a rasped silvery appearance, turn brown and shrivel. Damage is most severe when cold, wet or dry conditions slow seedling growth.
Strategic prevention may involve foliar spraying in the previous spring. Clean cultivation in autumn and attention to weeds on fence lines is also essential. If possible, keep a distance from paddocks of the species that host mites, such as other pulses, pasture legumes (including sub clover and lucerne) and oilseeds, and control weeds such as thistles and capeweed along paddock borders and non-crop areas.
Bare earth insecticides that are registered in lentil for post-sowing use will protect germinating seedlings, when the crop is most vulnerable. Seed treatments work best when low numbers of mites are active during germination.
Monitor young crops weekly, inspecting lentil plants at 10 different sites within the crop. Weather conditions affect mite activity. If the weather is fine, estimate the numbers per leaf; if it is cold and cloudy, estimate the numbers per 100 square cm (10 cm x 10 cm) around the base of the plants. Mite damage is typically greater around the edge of paddocks where mites are invading from outside the paddock. An average of 50 mites per area inspected (leaf or around the plant base) indicates that control may be warranted.
The lucerne flea (Sminthurus viridis) is a small, wingless, light green, flea-like insect that jumps when disturbed. Symptoms of damage are a ‘window pane’ hole in leaves or ragged leaf edges. The host species range for flea is similar to that for RLEM. Control of lucerne flea is also similar to that for RLEM.
Monitor crops regularly, at least weekly, for signs of damage. If lucerne flea is suspected, look for the presence or absence of damage on 10 plants, repeated at five sites. An average of 10 or more holes per leaf may indicate that control is warranted.
Flowering and podding pests
Native budworm (Helicoverpa punctigera) moths migrate from inland Australia into lentil production areas in spring. Female mo