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Insect of the Month - Tarnished Plant Bugs | |
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| Causal Agent: Lygus lineolaris (& other species)
Crops Affected: Wide host range – many fruit, vegetable, field and forage crops and weed species
Life Cycle:
- One of the most serious & widespread of strawberry pests
- Sucking insects that pierce flower buds, blossoms, and developing fruits and plant parts
- Adult has distinctive triangle or “V” mark on back; strong fliers
- Overwinter as adults in leaf litter or under debris and migrate into fields in spring or fall to feed on weeds and crops
- Lay eggs in spring in plant tissues
- Young (nymph) resemble aphids without cornicles (tail pipes) and move more quickly; hatch & feed on developing blossoms & fruit
- Nymphs feed through May and June, maturing in late June to early July
- Most of damage results from nymphal feeding
- Adults feed on developing fruit
- Leave with fruiting complete in June or July (strawberries)
- May have 2-3 generations per year (depending on season length)
- Due to the fact that day neutral strawberries are flowering when TPB numbers are high, damage potential is higher
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Tarnished Plant Bug - adult | Tarnished Plant Bug damage | Tarnished Plant Bug damage - catfacing |
Photos by Robert Spencer |
Symptoms:
- Presence of insect life stages
- Range of damage to vegetables: reduced fruit set in bean, pepper & eggplant; blemishes on tomato fruit; necrotic spots on florets & curd of broccoli, cauliflower and heads of lettuce; dead leaves on potatoes; foliar injury on cucumbers; gummosis on zucchini
- Raspberries (most damage occurs after petal fall)
- Feeding on flower blossoms & developing fruit = crumbly berry
- Reduced plant vigour
- Saskatoon berries
- Yellow, aborting flower buds; droplets of brownish liquid may exude from newly pierced buds
- Fruit deformation
- Strawberries
- Feeding by nymphs – Nubbins or deformed fruit / Apical seediness
- Adult feeding – CATFACING
NOTE: Catfacing can be caused by other factors, producing identical symptoms
- Feeding also reduces plant vigour due to removal of plant nutrients
Monitoring:
- Be aware of neighbouring crops that might be a host or that might release a large number of adults when cut (e.g. alfalfa or canola)
- Crop should be monitored for the number of nymphs in flower blossoms. Sweep nets can determine adult numbers
- Scout the field perimeter in new fields or entire established fields
- Start monitoring in overwintered fields when they are uncovered onward
- Blossoms may be sampled from across the field, counting the number of nymphs and adults present
- Survey the field from pre-bloom until green fruit stage (strawberries)
- Tap plants or shake fruit clusters over a non-metallic pie plate
- Count the number of nymphs per 100 clusters
- Strawberry Economic threshold = 1 nymph or adult per 8 blossoms
Management:
- Careful monitoring of TPB populations
- Remove weeds (especially leguminous species)
- Ensure alternate host crops are not planted too close (e.g. alfalfa)
- Make careful and timely chemical control applications
- Controls are available with application timing restrictions
- Chemical control is challenging due to continuous flowering and fruiting of day neutral strawberries
- Only products with short Pre-Harvest Intervals (PHI) may be used
- Do not apply products when bees are actively working
Tarnished Plant Bug – A Major Pest of Strawberry – OMAFRA article
Tarnished Plant Bug – Video |
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For more information about the content of this document, contact Robert Spencer.
This information published to the web on April 26, 2018.
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