How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Ptycholoma (=Clepsis) peritana
(Reviewed 6/08, updated 6/08)
In this Guideline:
The adult has the typical bell-shaped tortricid moth wings while at rest. It is buff-brown and about 0.25 inch (6 mm) long. Each of the forewings is marked with a dark brown diagonal stripe and a marginal spot producing a chevron pattern when at rest. The anterior edge of the brown stripe is bordered by a faint whitish line. This character and the overall lighter color distinguishes adult garden tortrix from moths of the orange tortrix.
The slender larvae are nearly 0.5 inch (12 mm) long when mature. Larvae have light brown-green bodies and light brown heads. The head has a small, distinct dark brown spot on each side. Larvae and pupae overwinter in trash around the base of the plant.
Adults aren't usually seen until March or April. Larvae hatching from eggs laid in spring on older leaves move down into the trash where they feed on dead and decaying leaves. They construct shelters by tying bits of trash together. As a result of overlapping generations, all stages are generally present in spring and summer.
Larvae feed on dead and decaying leaves and fruit most of the time and generally cause no significant damage. However, as the population increases and the plant canopies close in, more ripening berries settle down into the trash among the tortrix larvae. When this happens, larvae will often spin a nest in creases along the berry's surface and may chew small, shallow holes in the berry, incidental to their scavenging. Thus, with the higher populations often attained by late spring or early summer, significant fruit losses can result from both larval contamination and secondary rots invading the feeding holes.
Contamination of South Coast fields just before the berries are sent to the processors during late June and July can be a serious problem. Up until the point when garden tortrix begins feeding on or webbing against the fruit, this insect serves a valuable function in breaking down and recycling old leaf and fruit litter.
In areas with a chronic tortrix problem, such as the South Coast, it may be feasible to remove accumulated trash in spring around the plants with either blowers or suction devices to limit the potential for a large population buildup. In severe situations, extra help may be required to sort out contaminated or damaged berries during harvest.
Treatments may be required in May to early July if large populations are present, but larvae are difficult to control with sprays because they are located in the litter beneath the protective canopy of strawberry leaves. Directed sprays that penetrate the foliage canopy at sufficient volume are recommended. Because of overlapping generations, there is no best timing period.
Organically Acceptable Methods
UC IPM Pest Management Guidelines:
Insects and Mites
Acknowledgment for contributions to the Insects and Mites: