Insect Pests of Saskatoons

An important part in the production of any fruit crop is to know what type of insects could cause production losses. A crop is at risk throughout the fruiting cycle. Insects can attack plants during flowering, fruit formation or just before harvest of the plump, juicy berries. A successful pest management program includes: insect identification; pest number and damage monitoring; what population numbers warrant control and knowing when the pest can be effectively controlled.

Apple Curculio
(Tachypterellus quadrigibbus)

Identification

• 5 mm long, reddish brown weevil with a long curved snout

• adults appear 5-10 days after petal fall
• adults lay eggs, one per fruit, about 28-33 days after the peak flowering period
• egg laying punctures on the young fruit are at the base close to the stem
• the puncture is sealed with excrement
• larval development takes less than 31 days, pupation less than 7 days
• larva feed on the developing seed in the fruit
• adults emerge from fruit mid July
• adults drop to ground and overwinter in leaf litter
• there appears to be no feeding after emergence

• misshapen, hard fruit

• adults are a 6 mm long sawfly with yellow with brown markings
• mature larvae are 6 mm long with yellow-brown head

• appears in May, just prior to maximum flowering (25% bloom)
• lay eggs in the nectaries of flower blossoms, the position is marked externally by a dark scar along the calyx of the flower
• one egg is laid in each flower
• eggs hatch after petal drop
• the larvae feed on the top of developing fruit
• on average, one larva will ruin 2 fruit per cluster
• the last fruit attacked is completely hollow
• mature larva drop out of the fruit at the end of June
• overwinters in the soil
• pupates in the spring
  
  

• can cause large numbers of fruit to drop
• more than 90% of the potential fruit crop can be lost
• causes fruit to be hollow and mummified

• blue-black in color with white woolly masses on posterior end

• overwinters on an elm tree as an egg
• the egg hatches into a "stem" mother; which moves to the leaves, where she starts feeding
• without mating, the stem mother gives birth to live young
• while feeding, the aphid injects fluid into the elm leaves, causing the leaves to curl and galls to form
• approximately the time the wild roses and lilacs bloom, aphids move from the elm tree to the roots of the saskatoon and establish colonies there
• in the fall, the aphids return to the elm tree to lay eggs for overwintering

• heavily infested saskatoons may fail to leaf out in spring
• moderately infested saskatoons may leaf out in spring, but will not grow vigorously
• may have small chlorotic leaves
• once exposed to hot weather, the plants die
• seedlings and plants less than 5 years old seem to be most affected

• adults are stout bodied moths, chocolate brown to dark buff in color with two whitish bands across the front wings
• wingspan of 30-40 mm
• the caterpillar has a black back with a whitish middorsal stripe
• the sides of the caterpillar body are light blue with sparse hairs
• the cocoon is multi-layered and yellowish white

• the eggs are laid at the base of host plant, within 30 cm of ground
• they are covered with a frothy substance
• they hatch in the spring with a flushing of host foliage
• the caterpillar construct silken nest near fork in stem
• when feeding, the caterpillar move out from nests leaving a trail of silk behind
• they return to the nests at night or during bad weather
• they feed for 6-8 weeks, depending on the weather
• then spin a cocoon and emerge in about 3 weeks
• one generation per year

• the caterpillars spin webbed tents around leaves and branches of host plant
• they feed inside the tent
• repeated defoliation results in a setback of fruit production

• a diverse group of moths
• the caterpillar is slender, green to brown, 12 mm in length with a dark-brown or black head
• usually very active and moves backwards when disturbed

• the eggs are laid on leaves
• the larvae change from pale green to greyish brown as they mature
• the larvae roll a leaf around their body to pupate
• could be 2 generations per year

• holes are eaten in leaves, later the leaves are folded in half and webbed together, which causes the leaves to turn brown and die
• leaf rolling includes the fruit, resulting in lower yields

• the adult is a small greyish-black moth with tinges of brown
• the larva is a light green to whitish worm, with dark head

• adult emerges in April, lays eggs at bud base and in crevices of bark
• larvae hatch in late April to early May
• larvae burrow into the buds around the time of flower bud break (green tip) to tight bud cluster
• they feed on the interior of flower buds
• as the insect matures, they web individual flowers in the flower cluster together and continue feeding
• larva numbers of 1 or more per bud cluster are common
• larva development is complete shortly after the flower petals fall

• adults are 5-6 mm long, 2.5 mm wide and flattened
• they are pale green to reddish-brown in colour with a distinct triangle or "V" mark 1/3 way down back
• they are difficult to see because they fly or move rapidly
• young nymphs are dull blue-green
• they look similar to aphids, but lack cornicles and move much faster

• adult overwinters under debris or plant cover along fence lines
• in the spring, they feed on early growing plants
• they mate, then migrate to crops suitable for feeding
• egg laying begins as early as mid May (in south) to mid June (in Peace country)
• nymphs develop into adults in 12-34 days, depending on the temperatures -- the hotter the weather, the faster they develop
• they are strong flyers

• when feeding, the Tarnished Plant Bug punctures the plant tissue and sucks the sap

• small, silver white moth with dark gold markings
• present in June and again in late July to mid Aug
• the light green caterpillar is 7 mm when full grown

• overwinters as an egg on leaf buds
• the larva tunnel into young shoots in May
• the larva exits the stem, then pupates

• late May or early June--new green shoots wither and die
• look for a small hole at the base of the stem and cut open, then look for light a green caterpillar

• the adult is oval or rectangle in shape
• it has a lace-like appearance and the head is covered with a hood
• the larvae are identical to the adults, just smaller

• the eggs are laid in early spring on leaf underside
• the eggs hatch in 3 weeks, then the larvae feed on the leaves
• the adults emerge in mid summer
• the second generation completes its development by early fall
• overwinters as adult in leaf litter

• mottling of foliage
• leaves become leathery and tend to drop prematurely
• will also leave dark, tarry excrement drops on the leaf underside

• the adult is a slender fly
• the larvae are small, legless maggots

• little is known of the life cycle

• finger-like galls on the leaves
• they do not cause serious damage to the host plant

• green-black, slug-like larva
• adults are a shiny black sawfly and house fly size

• two generations per year
• adults lay eggs in slits in leaves

• larvae rasp away the leaf surface
• skeletonized leaf turns brown and dries up
• feeding damage occurs in June and again in late August