NC State Extension

Controls Based on Treatment Windows – Spring

SPRING: APRIL THROUGH BUD BREAK

Prior to bud break — AprilStages of pests. In April and early May, most pests are very active.

  • RBM — Mites in buds.
  • EHS — All stages present. Crawlers becoming more common.
  • BWA — Adults may start to lay eggs.
  • BTA — Eggs continue to hatch. Stem mothers, the first twig aphid form, are molting into adults and will start to produce live young which quickly increases numbers.
  • Cinara aphids — Cinara aphids continue to be very active.
  • SSM — Spider mites are starting to hatch and feed.
  • HRM — Rust mites very active. Numbers continue to increase.
  • Predators — Most predators are starting to be more active and commonly found. The activity increases as temperatures increase.

Advantages to spring applications. April is a good time of year to control most pests. It is certainly the traditional treatment window for Fraser fir pests.

Typically rosette bud mites are controlled during shoot elongation. However, RBM can be controlled before bud break using the systemic product, Movento. There are some indications that use of this product with a mistblower is providing good RBM control.

Disadvantages to spring applications. One of the disadvantages to treating for pests in the spring is finding time to do it. With planting, fertilizing, and even herbicide applications, there often isn’t enough time to treat for insects. Also, the weather is quite variable. It is often windy and rainy, making it hard to find ideal conditions for application.

Twig aphid control can be hampered by the production of cones on the trees. Once the cones are produced, the aphids can hide under the bracts and be protected from insecticide applications. One product that still works once cones are present is Dimethoate which is quick acting and slightly systemic. If other products are used, either apply before cones are formed, or remove the cones before treatment.

Another disadvantage to spring applications is that is greater impact on predators and pollinators. Treatments made with the synthetic pyrethroids may cause rust mite outbreaks the following year. Bees are attracted to purple deadnettle and wild mustard. Protect bees by either removing flowering ground covers or spraying in the evening or night.

Spring is also not the ideal time to treat for EHS. If one goal of applications is to treat for EHS, wait as close to bud break as possible.

Materials That Can Be Used from April through Budbreak
Pesticides RBM EHS BWA BTA* Cinara** SSM HRM
Bifenthrin products(Talstar, Sniper) None None Excellent Excellent Excellent Excellent None
Asana None May be some suppression but not long lasting control. Excellent Excellent Excellent Non. None
Dimethoate None May be some suppression but not long lasting control Poor Excellent Excellent Excellent control of active mites but eggs not controlled. Excellent control of active mites but eggs not controlled.
Asana + Dimethoate None Wait as close to bud break as possible for better control. Excellent Excellent Excellent Excellent control of active mites but eggs not controlled. Excellent control of active mites but eggs not controlled.
Safari None Is probably too early to get good control. Excellent None Good None None
Movento Good Poor Excellent Good Good Unknown. May have some activity. Unknown. May have some activity.

*BTA control is for that spring. Control will not carry over to the following year.

**Cinara aphid control is for that spring. If trees will be cut in the fall, trees will have to be retreated that time.

For more information on mite control see: Focus on Mite Control.

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