Thanks for signing up!

Look for the Digest in your email twice a month.

Follow Us

Sign up for our Digest to receive the latest agronomic insights and crop management advice for your primary growing region delivered twice a month to your inbox.

Beware of Navel Orangeworm During Almond Hull Split

June 5, 2019
This agronomic image shows naval orangeworm moth

Hull split is an exciting time of year, not just for growers, but also for pests like navel orangeworm (NOW). Hull split is when almonds are most susceptible to damage from NOW, so it is crucial to have a preventive plan on how to control this devastating insect.


At NOW’s larval stage, they bore into the nutmeat of almonds. As they grow, they can consume most of the nut while producing large amounts of webbing and frass. Damage made by NOW can lead to fungal infections and disease.


Navel orangeworm moths can be identified by their irregular gray and black forewings and legs. Moths lay white eggs on mummy nuts that are left over from the previous harvest and on newly-exposed nuts after hull split. Larvae can be spotted by their reddish brown heads and crescent-shaped markings behind the head. Pupae can be found inside the hull of the nut.


  • Remember that it’s better to be too early in your spray timing than too late. By the time many almonds begin splitting, only a small window exists to protect exposed nuts. Follow up with an additional spray about 2–3 weeks after the first application.
  • Include Besiege® insecticide at hull split to deliver effective control of NOW. Besiege provides broad-spectrum lepidopteran control with excellent knockdown and long-lasting residual. Harvest almonds at 95% of hull split to reduce the risk of NOW infection.

Hear from Garrett Gilcrease, Syngenta agronomic service representative, for additional benefits from using Besiege.

Sign up for the Know More, Grow More Digest to receive twice-monthly agronomic e-mail updates pertinent to your area.

All photos are either the property of Syngenta or are used with permission.

Syngenta hereby disclaims liability for third-party websites.