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Ministry of Agriculture, Food and Rural Affairs

Mullein Bug

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Beginner

Scientific Name
Campylomma verbasci

Identification

  • Regarded as an early season pests of apples from bloom through until 2-3 weeks after petal fall. After that time they are considered important predators of aphids and mites.

Eggs:

  • 0.8 mm long.
  • White and flask shaped.

Nymphs: 

  • Five nymphal instars.
  • 0.5-2.5 mm long, yellow to green, with a pointed head and red eyes. 
  • Third instar nymphs have spots on their legs, which carry through to the adult stage.  

Adult:

  • 3 mm long.
  • Oval.
  • Light green to tan in colour.
  • Antennae are four segmented and prominent. 
  • Hind legs have black spots and are spine covered. 

Often Confused With

  • Aphids - Aphids have cornicles or tail pipes at the tip of the abdomen, which mullein bugs lack, and are slow-moving
  • White apple leafhoppers - White apple leafhoppers have a more elongated body and short antennae.  The wings of leafhopper adults are held roof-like over the body.  White apple leafhoppers lack the dark spots on the legs observed in mullein bug adults and late instar nymphs.
  • Tarnished plant bug - Tarnished plant bug adults are much larger, are darker in colour and have a distinct Y on their back, behind the head. 

Interaction With Host
Nymphs initially feed on plant sap attained from leaf veins, and also sting developing fruitlets. Several weeks after petal fall, nymphs become predaceous and begin feeding on prey such as European red mite and aphids. Nymphs with red bellies are an indication the nymphs have been feeding on mites.

Period of Activity
Nymphs are active from bloom to pre-harvest.

Insects Attacked
Generalist predator feeding on phytophagous mites, eggs, and aphids.

Monitoring and Management
Begin monitoring for nymphs during bloom and continue until two or three weeks after petal fall. Monitor mullein bug using tapping trays. For instructions on how to construct a tapping trap, click here.  After petal fall, monitor for mullein bug on the leaves and terminals of apple trees.

Advanced

Scientific Name
Campylomma verbasci

Identification
This bug is regarded as an early season pests of apples from bloom through until 2-3 weeks after petal fall. After that time they are considered important predators of aphids and mites.

Eggs: Eggs are 0.8 mm long, white and flask shaped.

Nymphs: Mullein bugs develop through five nymphal instars to adults. Nymphs are 0.5-2.5 mm long, yellow to green, with a pointed head and red eyes. Third instar nymphs have spots on their legs, which carry through to the adult stage.   

Adult: Adult mullein bugs are 3 mm long, oval and light green to tan in colour. Antennae are four segmented and prominent.  Hind legs have black spots and are spine covered. 

Often Confused With

  • Aphids - Aphids have cornicles or tail pipes at the tip of the abdomen, which mullein bugs lack, and are slow-moving
  • White apple leafhoppers - White apple leafhoppers have a more elongated body and short antennae.  The wings of leafhopper adults are held roof-like over the body.  White apple leafhoppers lack the dark spots on the legs observed in mullein bug adults and late instar nymphs.
  • Tarnished plant bug - Tarnished plant bug adults are much larger, are darker in colour and have a distinct Y on their back, behind the head. 

Interaction With Host
Mullein bug overwinters as eggs inserted deep into the bark of one- or two-year-old wood of apple. Eggs begin hatching during bloom and continue to hatch into the petal fall period. Most years the hatch is synchronized with peak emergence at early petal fall. 

Nymphs initially feed on plant sap attained from leaf veins, and also sting developing fruitlets. Several weeks after petal fall, nymphs become predaceous and begin feeding on prey such as European red mite and aphids. Nymphs with red bellies are an indication the nymphs have been feeding on mites. Nymphs progress through five instars before becoming adults.  Both nymphs and adults are fast moving, and adults are often quick to take flight if disturbed. The adults migrate to mullein plants, common along ditch banks and the sides of roadways in Ontario, where they feed throughout the summer months. Season-long monitoring in apple orchards indicates some mullein bugs remain in the orchard during the summer. During that time they are considered important predators of aphids and mites. In late fall, female mullein bugs return to apple trees and lay overwintering eggs into young wood. There are two to three generations per year.

Period of Activity
Nymphs are active from bloom to pre-harvest.

Insects attacked
Generalist predator feeding on phytophagous mites, eggs, and aphids.

Monitoring and Management
Begin monitoring for nymphs during bloom and continue until two or three weeks after petal fall. Monitor mullein bug using tapping trays. For instructions on how to construct a tapping trap, click here.  After petal fall, monitor for mullein bug on the leaves and terminals of apple trees.