Category : Insects
Blackheaded fireworm
Rhopobota naevana
Symptoms
Several leaves webbed together at growing tips of fresh growth; insects feed on lower leaf surface, creating holes which remain covered by the upper leaf surface; upper leaf surface turns red-brown and dies; insect may also wound fruit and encourage secondary infections with fungi and/or bacteria; adult insect is a gray-brown moth; larvae are cream to gray-green caterpillars shiny dark brown or black head
Cause
Insect
Comments
Management
Reflooding the beds for between 24 and 48 hours after eggs have hatched will kill off a high number of larvae; application of Bacillus thurengiensis may reduce the populations of larvae on the plants
Cottonball
Monilinia oxycocci
Symptoms
Tip blight on new shoots (shriveled tip resembles a shepherd's crook); masses of white powdery spores on tips just before plant bloom; brown V- or U-shaped lesions on leaf midveins
Cause
Fungus
Comments
Management
Primary method of controlling cottonball is the application of appropriate fungicides if available; cultural practices that reduce incidence of the disease have not yet been investigated
Cranberry blossomworm
Epiglaea apiata
Cranberry blossomworm larva
Cranberry blossomworm - adult moth
Symptoms
Feeding damage to leaves; holes bored in buds; buds and blossoms dropping from plant; adult insect is a dark brown moth; young larvae are green caterpillars which turn reddish-brown sa they mature
Cause
Insect
Comments
Management
Insectide application is recommended for commercial production if the number of blossomworm larvae reaches the threshold of 4.5 larvae per 25 sweep net samples (sweep netting must be done at night as the insect is nocturnal);
Cranberry fruitworm
Acrobasis vaccinii
Cranberry fruitworm (berry pictured is blueberry)
Symptoms
Berries turning red prematurely; fruit shriveling and drying up; fruit is hollowed out and filled with insect frass; entry and exit holes may be visible on the berry - exit holes are significantly larger than entry holes; adult insect is a gray-brown moth which lays its eggs near the calyx end of the berry; newly hatched larvae are very small and are pale yellow in color; larvae are the damaging stage and they burrow into the berries to consume the pulp inside
Cause
Insect
Comments
Management
Predation by natural enemies does occur but is not enough to keep the cranberry fruitworm under control; late flooding of the cranberry plantation (30 day reflood before the end of dormancy) has een shown to successfully reduce the activity of the fruitworm; chemical control option include several broad spectrum insecticides for commercial use but must be applied at the egg stage in order to be effective as larvae which have already entered the fruit are shielded from the chemical
Cranberry tipworm
Dasineura oxycoccana
Symptoms
Cupping and whitening of terminal leaves; death of growing tips of plants; plants will compensate by creating a new branch at a lateral bud, these new branches may produce only vegetative growth and no fruit, resulting in reduced yield the following year; adult insect is a tiny (2 mm) fly which only lives a few days; larvae are maggots which are initially clear but change to white and finally orange as they mature
Cause
Insect
Comments
Management
Because cranberry tipworm larvae and adults are so small, they are difficult to monitor; sanding the cranberry bushes is an effective method of controlling insect emergence as it prevent that adults emerging from pupae in the soil; sanding should be conducted on continuous blocks as there is potential for the insect to recolonize from unsanded areas; natural enemies include hoverflies and some species of parasitic wasp
Cranberry weevil
Anthonomus musculus
Symptoms
Flowers are orange instead of pink due to feeding damage and do not produce fruit; numerous holes in berries; feeding damage to underside of leaves results in small black crescent-shaped spots; damage to the base of runners by adult insect may cause damage similar to frost; adult insect is a reddish brown beetle with elongated snout; larvae are yellow-white grubs
Cause
Insect
Comments
Management
Cranberry weevil populations usually remain low and little is known about their natural enemies and cultural control methods; chemicals registered for use in commercial plantations on the East coast of the US include azinphosmethyl and chlorpyrifos which should be applied if weevil population has reached the threshold (on average 4.5 weevils per 25 sweep net samples)
Gypsy moth
Lymantria dispar
Gypsy moth larva
Symptoms
Feeding damage to cranberry foliage and terminal buds and new growth; adult insect is a brown (male) or white (female) moth; larvae are black caterpillars which are covered in hair-like structures called setae; as the caterpillars mature they develop five pairs of raised blue spots and six pairs of raised red spots along their backs
Cause
Insect
Comments
Management
Larvae are easily controlled with insecticides or by reflooding the beds for a period of 24 hours