Joe Cacka and the White Grub

Tanner Sheahan

This post is dual purposed.  We want to officially introduce Joe Cacka, Cascade/Columbia Division Agronomist and also highlight one of his recent research projects.

Joe has conducted over 2000 agricultural research trials in the past 24 years working for Western Farm Service and now Crop Production Services (CPS).  Joe brings with him a degree in Integrated Pest Management, MSc. and a Crop Science, BSc. both from OSU.

He has worked on a diverse number of crops including grass seed, clover seed, corn, beans, blueberries, cane berries, hops, cherries, hazelnut, and Christmas trees.  Testing new products coming to market and refining the use of older products has be part of his responsibilities.  He has developed crop monitoring programs (CMP) in tall fescue, perennial ryegrass grown for seed, and hazelnuts.  He is currently working on blueberries and wheat CMP’s for the Willamette Valley producers.  Joe and Paolo Sanguankeo his research assistant will conduct over 75 new trials this year.

One of Joe's projects this year is a fairly new problem found in Christmas tree production. 

A Serica spp. Beetle sometimes called a `June Beetle’ is causing significant damage to noble fir, nordman fir and others.  The larvae of this beetle is often referred to as a `white grub’ causes severe root feeding during the fall through the winter and early spring.  This feeding when populations are high reduced the trees ability to draw nutrients and moisture during the growing season leaving trees looking drought stressed with needles desiccating and dropping off and possibly resulting in tree death.

Serica spp. "White Grubs" to the left and the adult beetle below.

The adult beetle are 5-8 mm (0.25 – 0.3”) long and 3-5 mm (0.12 – 0.25”) wide.  They emerge in early June and are found in the fields through Sept. The larvae are a `white grub’ which can be found from  July through May.  The larvae will grow to 12-17 mm (0.5-0.6”) long.

Damage caused by the `white grub’ larvae of the Serica spp. Beetle.

Joe and the agronomy team is working on identification of the pests and learning their life cycles and developing control and management strategies.

If you are growing Christmas trees and are seeing these symptoms, contact your local CPS fieldsmen and he will work with you and the agronomist to determine the cause of damage.