Newly Hatched Bagworms Are Set to Cause Damage

If you haven’t scouted for bagworms yet, trust me – they are out and about! They are a recurring pest in our area and can cause significant damage to landscape plants. Unfortunately, many homeowners do not become concerned about bagworms until they notice the large bags hanging from trees and shrubs. By that point, the damage has often already been done. Fortunately, the ideal window for control is approaching.

Bagworms overwinter as eggs inside the protective bags left by female moths. From mid-May through mid-June, larvae hatch and emerge through the bottom opening of the old bag. They immediately begin constructing their own miniature silk-lined bags, incorporating bits of foliage into the structure for camouflage. Once the bags are completed, the young larvae begin feeding. As the larvae grow, their bags expand.

By mid- to late August, feeding is complete. The mature larvae firmly attach their bags to twigs and branches, where they remain protected as they complete their life cycle.

Bagworms are most commonly found on eastern redcedar and juniper, but they also attack arborvitae, spruce, and pine. In addition, many broadleaf trees, shrubs, and ornamental plants can serve as hosts. After defoliating a plant, bagworms may migrate in search of additional food sources, attacking either the same species or entirely different plants.

The extent of damage can range from minor to severe. As larvae grow larger, their appetite increases dramatically. In some cases, what appears to be a healthy tree can become heavily defoliated in a very short period of time. Several consecutive years of severe feeding can weaken and eventually kill trees, especially conifers.

There are two primary methods of bagworm control: cultural and chemical.

For those who prefer not to use insecticides, handpicking bags from infested plants can be an effective management strategy. This is often easiest during the winter months when the bags are more visible against dormant foliage and branches. However, it is important to remember that a single overlooked bag may contain hundreds to more than a thousand eggs. Handpicking also becomes impractical when plants are heavily infested or too large to reach safely.

Chemical control is most effective when larvae are young and actively feeding. In most years, bagworm larvae begin emerging from overwintering bags in mid- to late May. Because egg hatch occurs over 4 to 5 weeks, treatment timing is important. Insecticide applications made in late summer are often ineffective because the larvae are larger, more resistant, and may have already stopped feeding.

The third week of June is generally the ideal time to apply insecticides for bagworm control. Products containing spinosad, acephate, cyfluthrin, or permethrin are commonly used and are available under a variety of trade names. Always read and follow label directions, and check the active ingredients to ensure the product is labeled for bagworm control.

For more information on managing bagworms, please get in touch with me at your local K-State Extension, Southwind District office in Iola, Erie, Fort Scott, and Yates Center.

Krista Harding is a K-State Research and Extension Horticulture agent assigned to the Southwind District.  She may be reached at [email protected] or 620-244-3826.

K-State Extension is an equal opportunity provider and employer.

Cost-Share Dollars Available for Forage Testing

To help producers make informed feeding decisions, K-State Extension – Southwind District has been awarded funding through the Bill House Ag Grant from the Community Foundation of Southeast Kansas. Through this grant, we are offering a $20 cost-share on full nutrient forage analysis tests to producers of the Southwind District. A typical total nutrient analysis test costs $22 plus shipping, while a full nutrient analysis plus nitrate test costs $35 plus shipping. The program is available on a first-come, first-served basis and is limited to 100 total samples. Producers may receive cost-share assistance on up to two forage samples.

Though the feeding season is a few months away, we are beginning to start the summer haying season. As producers bale hay, many of them are beginning to evaluate hay inventories and maybe even plan winter supplementation. One of the most overlooked management tools is also among the most economical: forage testing.

A common assumption is that all hay is relatively similar, especially when it looks good from the outside. Unfortunately, appearances can be deceiving. Two hay bales harvested from neighboring fields can vary significantly in protein, energy, digestibility, and even nitrate content. Without knowing the nutritional value of your forage, developing an effective feeding program becomes little more than an educated guess.

This year, forage testing may be more important than ever. Across southeast Kansas, weather conditions and harvest timing have created significant differences in forage quality. Hay baling has been significantly delayed due to rain or other environmental factors, such as flooding. As a result, nutrient values ARE going to vary widely this year, especially on cool-season forages still not harvested in June.

Knowing the quality of your forage can provide several benefits:

• Stretch feed dollars by matching supplements to actual forage needs.
• Avoid overfeeding expensive protein and energy supplements.
• Identify lower-quality hay that should be fed to cows with lower nutrient requirements.
• Reduce the risk of nutritional deficiencies that can affect reproduction, body condition, and calf performance.
• Detect potential issues such as nitrate accumulation or other feed quality concerns.

For many operations, the cost of a forage test can be recovered quickly through more precise supplementation decisions. Feeding even one pound of unnecessary supplement per cow per day can add up to substantial costs over the course of a winter-feeding season.

A full nutrient analysis provides valuable information, including crude protein, total digestible nutrients (TDN), fiber levels, energy, and other important nutritional measurements that can be used to balance rations more effectively.

Collecting a representative sample is critical. Producers are encouraged to use a hay probe and sample multiple bales from each lot of hay. Samples can then be submitted through the Extension office for laboratory analysis.

The information gained from a forage test allows producers to make data-driven feeding decisions rather than relying on visual estimates or assumptions. In a time when feed costs remain one of the largest expenses in an operation, understanding the quality of your forage can be one of the best investments you make.

For more information about the forage testing cost-share program or assistance with collecting samples, contact Hunter Nickell, Livestock Production Agent at any K-State Extension – Southwind District office or by email [email protected].