Insect pest risk

High risk Moderate risk Low risk
Podsucking bugs
  • Sequential plantings of summer legumes (pest moves progressively from early to later plantings and can build to very high levels).
  • Water stressed plants (set fewer pods = greater % seed damage/bug population).
  • Late summer plantings (at greater risk than spring planted crops, particularly in southern Qld and in NSW).
  • Brown bean bugs (BBB), very common in mungbeans, mistaken for predatory bugs and not controlled.
Helicoverpa
Compensation for early helicoverpa damage is reduced in water stressed crops, and in late crops running into cooler autumn weather.
  • Mirid control at early budding (with dimethoate) increases risk of flaring helicoverpa above threshold.
  • Use of other non-selective pesticides in vegetative stages can also flare helicoverpa.
Bean podborer
  • Coastal mungbeans (Ayr, Bundaberg)
  • Sub-coastal crops (Kingaroy, Biloela) in high rainfall years.
 Crops in more inland regions (Downs, Emerald) in high rainfall years.
Mirids
Risk higher in warm summers with frequent north west winds. Mirid activity much lower in cool summers.
Cereal thrips
Spring crops planted close to winter cereals.
Two spotted mites
Crops close to poorly managed early maturing crops with a history of mites (e.g. cotton). Use of non-selective pesticides (especially synthetic pyrethroids) in vegetative stages may flare mites.
Other pests
Planting spring crops close to winter cereals increases the risk of cereal thrips.
  • Avoid planting in paddocks bordered by parthenium weed. Parthenium is a primary weed host for TSV (vectored by thrips).
  • Control of thrips to reduce TSV in susceptible crops is ineffective.

Pest incidence

Pest Crop stage

Emergence

Vegetative

Flowering

Podding

Podfill/Grainfill
Bean fly Damaging
Thrips Damaging Present Present
Loopers Damaging Damaging Present
Helicoverpa Damaging Damaging Damaging Damaging
Aphids Damaging Damaging Present
Mirids Present Damaging Damaging Damaging
Podsucking bugs Present Damaging Damaging
Bean pod borer Damaging Damaging Damaging
Cluster caterpillar Damaging Damaging Damaging

 

Present Present in crop but gen­er­ally not dam­ag­ing
Dam­ag­ing Crop sus­cep­ti­ble to dam­age and loss

Key IPM strategies for mungbeans

  • Mungbeans are most susceptible to pests from budding onwards.
  • Vegetative mungbeans can tolerate up to 33% defoliation without yield loss. Tolerable defoliation drops to 15-20% once flowering and podding commences.
  • At flowering, under good growing conditions, mungbeans can compensate for moderate levels of early damage by setting new buds to replace those damaged by pests. Excessive early damage leads to uneven pod ripening and delayed harvest.
  • Stressed crops are less able to compensate for pest damage.
  • Shorten the crop flowering period by planting on full moisture profile and water crops just before budding
  • The addition of a salt (NaCl) adjuvant to some chemicals at reduced rates (targeting mirids, pod sucking bugs and aphids) can still provide good efficacy on pests while reducing the impact on beneficials, but may also reduce residual effectiveness.

Insecticide resistance

  • H.armigera is resistant to synthetic pyrthroids (SPs) and has previous carbamate resistance issues.
  • Redbanded shield bug is resistant to SPs. The addition of a 0.5% salt adjuvant to deltamethrin-based pesticides achieves up to 60% control.
  • Bean podborer is resistant to synthetic pyrethroids – consider using a product other than a SP.
  • Smudge bugs, important aphid predators, are also resistant to SPs.

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