Insects of Southern Australian Broadacre Farming Systems - Grains ...

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Lepidoptera: Plutellidae Diamondback moth - DBM (Plutella xylostella) Distinguishing characteristics/description larva 10 mm 20 30 40 50 Larva Head capsule lightens as matures adult Adult Beak-like mouthpart Larvae slightly tapered at each end. Pale yellowish green in colour ‘Diamond’- shape pattern on wings at rest Body covered in coarse black hairs Mesh-like pupal casing Leaf mine of 1 st larval instar Eggs are pale yellow, oval and about 0.5 mm in length. Eggs are laid singularly or in clusters along the leaf margins. Larvae develop through four instars. The first two instars have a dark head, but the first instar is not visible as it lives and feeds inside leaf tissue (its presence is indicated by a leaf mine). Larvae wriggle vigourously when disturbed and often drop from the plant on a silken thread. The pupal casing is mesh-like in appearance and the pupa inside is cream-green initially, but darkens before the adult emerges. Four abdominal prolegs Nearly complete crochet arrangement at base of prolegs Confused with/similar to Anal prolegs Diamondback moth (DBM) larvae can be confused with young cabbage white butterfly (Pieris rapae) and cabbage centre grub (Hellula sp.) larvae. Distribution, pest status and risk period DBM is a worldwide pest with a high propensity to evolve insecticide resistance. DBM is widely distributed in southern Australia. DBM has no diapause phase in Australia and has overlapping generations. All life stages can be present at any one time. Adults are active flyers but usually do not move far within a crop. SECTION 4 COMMON Pest, Beneficial AND EXOTIC Species 13 Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012
They are capable of long distance migration on prevailing winds, particularly when host material has died off. Weather conditions can impact dramatically on DBM populations. Development is faster in warm weather and slower in cool weather. For example, at 15 °C the life cycle takes approximately 36 days to complete, but at 28°C it takes approximately 11 days to complete. Crops attacked/host range DBM feeds on canola and all Brassica plants, including weeds. The availability of Brassica host plants can influence outbreaks. Summer rainfall can also provide a green bridge of summer weeds. DBM adults migrate from summer weed sources into canola crops in autumn and winter. Significant rainfall events (greater than 8 mm) can reduce larval abundance by drowning or dislodging larvae or facilitating death by disease. Monitoring/sampling Crops should be monitored using a sweep net at the first sign of damage and throughout the growing season from late winter to late spring. Take a minimum of five sets of 10 sweeps and calculate the average number of larvae per 10 sweeps. If spraying, it is important to monitor 5-7 days after spray application to assess the effectiveness of treatment. Management options Threshold guidelines indicate spraying is recommended when: • 50 larvae are collected per 10 sweeps for pre-flowering unstressed crops. • 30 larvae are collected per 10 sweeps for pre-flowering stressed crops. • 100-200 larvae are collected per 10 sweeps for unstressed crops with the majority of plants in flower. Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012 Damage symptoms Larvae can cause damage to all growth stages of the canola plant. They feed on the foliage before flowering and, as flowering progresses, an increasing proportion of the larvae move to the floral buds, flowers and pods. Maturing pods are surface grazed or scarred by the larvae. They are not as damaging as native budworm as they do not chew into the pods. Premature shattering of pods rarely occurs. Larger larvae feeding on the underside of leaves can create holes, often with the upper surface intact, producing a window effect. Canola can tolerate considerable foliar feeding damage before crop yield is affected. Severe feeding damage can cause complete defoliation resulting in yield reduction. 14 SECTION 4 COMMON Pest, Beneficial and exotic Species If monitoring detects a rapid increase in DBM larvae and numbers exceed spray thresholds, a two-spray policy is thought to be more effective than a single spray. The second spray should be applied approximately seven days after the first if more than 20% of the initial population remains. Good spray coverage is critical for effective DBM control as more than 20% of the larvae reside in the bottom third of the plant. You should consider the size of the majority of the larvae before making a management decision. Target treatment at larvae
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© Department 2012 Department of Pr
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Disclaimer The information provided
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Insects of Southern Australian Broa
Page 8 and 9: SECTION 1 Introduction Over 95% of
Page 10 and 11: What have I-spyed This flow chart c
Page 12 and 13: SECTION 2 Basic Insect Taxonomy, Ex
Page 14 and 15: Table 2.1 Taxonomic category Taxono
Page 16 and 17: Lifecycles and development Having a
Page 18 and 19: Important Insect Groups and Identif
Page 20 and 21: Introduction Insects of Southern Au
Page 22 and 23: Table 3.1 Mouthpart types and assoc
Page 24 and 25: Table 3.1 Mouthpart types and assoc
Page 26 and 27: Insects of Southern Australian Broa
Page 30 and 31: Identification Keys Larval forms to
Page 32 and 33: Moth/butterfly larvae to main famil
Page 34 and 35: Beetles (adults) to main families/s
Page 36 and 37: Crop Damage Pest Identification Key
Page 46 and 47: SECTION 4 Common Pest, Beneficial a
Page 48 and 49: Groups (families) relevant to broad
Page 50 and 51: ARMYWORMS Lepidoptera: Noctuidae Co
Page 52 and 53: CUTWORMS Lepidoptera: Noctuidae Com
Page 54 and 55: Cutworm - Turnip moth (Agrotis sege
Page 56 and 57: BUDWORMS Lepidoptera: Noctuidae Nat
Page 60 and 61: Lepidoptera: Pyralidae Lucerne seed
Page 62 and 63: BEETLES (Order Coleoptera) Coleopte
Page 64 and 65: COCKCHAFERS Coleoptera: Scarabaeida
Page 66 and 67: Damage symptoms BH pasture cockchaf
Page 68 and 69: Confused with/similar to Larvae are
Page 70 and 71: Confused with/similar to Larvae are
Page 72 and 73: White fringed weevil Small lucerne
Page 74 and 75: LADYBIRD BEETLES Coleoptera: Coccin
Page 76 and 77: CARABID BEETLES or GROUND BEETLES C
Page 78 and 79: BUGS (Order Hemiptera) Hemiptera -
Page 80 and 81: General aphid lifecycle and biology
Page 82 and 83: CEREAL APHIDS Corn aphid (Rhopalosi
Page 84 and 85: CEREAL APHIDS Russian wheat aphid (
Page 86 and 87: CANOLA APHIDS Cabbage aphid (Brevic
Page 88 and 89: PULSE APHIDS Blue green aphid (Acyr
Page 90 and 91: Hemiptera: Scutelleridae Sunn pest
Page 92 and 93: DAMSEL BUGS OR NABIDS Hemiptera: Na
Page 94 and 95: PREDATORY BUGS Hemiptera: Heteropte
Page 96 and 97: Larvae Larvae are legless and can b
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Page 100 and 101: Eggs are laid just below the leaf s
Page 102 and 103: HOVERFLIES Diptera: Syrphidae Vario
Page 104 and 105: EARWIGS (Order Dermaptera) Dermapte
Page 106 and 107: Damage symptoms: shredded leaf tips
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SPRINGTAILS (Class Collembola) Coll
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SLUGS & SNAILS (Order Pulmonata) Ga
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Management options Thresholds for c
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Management options No thresholds es
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Crops attacked/host range Grey fiel
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Acarina: Penthaleidae Redlegged ear
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Understanding the lifecycle of pest
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Crops attacked/host range A wide ra
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Acarina: Tetranychidae Bryobia mite
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WASPS, BEES & ANTS (Order Hymenopte
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Confused with/similar to These clos
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BENEFICIAL Distinguishing character
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EGG PARASITOIDS Hymenoptera: Tricho
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Bees as pollinators Bees provide a
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Lifecycle Complete metamorphosis. T
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More Information Website links DAFW
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SECTION 5 IPM Principles and Case S
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The IPM decision-making process IPM
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Biological agents GENERALIST predat
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Conservation and enhancing natural
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Table 5.1 Beneficial species common
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Host plant susceptibility and resis
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Selective insecticides The terms
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Conserving the benefits of insectic
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Step 4. What are the management opt
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Table 5.3 Pest species for which an
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Case study 2 Selective chemicals an
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Case study 4 Seed dressings protect
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6 Monitoring, Record Keeping, Sampl
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Introduction Monitoring pest and be
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Sending samples for identification
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• The dynamics of the pest popula
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Observer/recorder: Crop and variety
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Table 6.3 Check-list of common broa
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Table 6.4 Check-list of common pest
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Table 6.4 Check-list of common pest
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Biosecurity 7 Biosecurity
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If you see anything unusual, call t
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SECTION 8 Glossary Abdomen: the thi
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Labium: lower lip. Labrum: upper li
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References The information in this
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