Pests and Diseases

Pests and diseases can have a significant effect on the establishment, yield, and longevity of your forage crops. Make use of Penn State Extension’s recommendations for managing pests and diseases in forage crops such as grass hay, clover, corn, wheat, cereal, barley, and soybeans.

Common Forage Crop Pests and Diseases

The economic impact of a ruined forage crop can have far-reaching consequences for livestock producers. Being able to prevent the spread of disease and control pests is always high on a farmer’s list of priorities. Before this step, however, it’s important for you to be able to identify the most important pests and diseases that can threaten forage crops.

A variety of pests can affect alfalfa crops. If the weather is warm, it leads to increased populations of alfalfa weevils. When they are young, the weevils leave pin-hole sized holes near the tips of the plants, while older weevils leave jagged edges on the leaves. The alfalfa weevil is one of the two most-damaging insect pests of alfalfa in Pennsylvania. The potato leafhopper can also cause extensive and costly damage to alfalfa crops.

Black cutworm is often a pest of corn, but also causes problems in wheat and tobacco crops. Penn State Extension has been monitoring the arrival of black cutworm moths using pheromone traps.

winter grain mites are uncommon in Pennsylvania; however, mites were recently found in fields of rye that were being grown for silage in Chester County.

A range of pests can affect clover. The clover root curculio and the clover root borer can rescue or eliminate red clover stands. The clover root curculio is a common insect in Pennsylvania clover and alfalfa fields.

Forage grasses grown in humid temperature zones can be susceptible to diseases caused by plant pathogenic bacteria such as yellow slime disease and bacterial leaf blight. While barley yellow dwarf is one of the most widely distributed and destructive viral diseases that can affect small grains.

One way to reduce the risk of disease is to use high quality certified seed purchased from reputable suppliers. Fungicide applications can control various leaf diseases, but timing is crucial.

Forage Crops Pest Management

It’s possible to control pests by introducing an integrated pest management system. Combining biological, cultural, physical, and chemical tools allows producers to minimize economic, health, and environmental risks, while at the same time control pests efficiently and effectively.

Penn State Extension’s What's New in Agronomic Pest Control online course looks at the new developments in the agronomic pest market, including insect, disease, and weed control. The Penn State Agronomy Guide also contains a section on pest management.

The application of fungicide is one way to control diseases. Scouting and growth staging can help you decide whether to apply fungicides or you can enlist the help of a certified crop scout.

If your soil is healthy it can play a significant role in suppressing pests. Healthy soil supports a diverse microbial community that can suppress pests naturally. However, pests come in all shapes and sizes. Deer, for example, can cause significant damage to forage crops. Deer control options include the Deer Management Assistance Program (DMAP).

You should not overlook weed control in forage production. They can reduce yield by competing for water, sunlight, and nutrients. Some weeds are simply unpalatable to livestock, while others, such as poison hemlock, can be highly toxic.

Forage Crops and Pesticides Application

Pesticides can be used to minimize the loss of forage crops due to disease and pest attack. However, if you’re going to apply certain pesticides, such as restricted-use pesticides (RUPs) you have to be certified in accordance with EPA regulations and state, territorial, and tribal laws. Glyphosate, or Roundup, commonly used to control weeds, is not a restricted use pesticide. Private applicators and commercial businesses applying pesticides also have to keep records.

Penn State Extension has a range of online courses and in-person workshops for anyone looking to get certified or fulfill the continuing education requirements. The Agronomic Pesticide Update workshop offers 2 Core and 2 Category (PC, 01, 18) credits, for example. The Certified Crop Adviser (CCA) program covers pest management. Growers of soybean can join others for an informative workshop and demonstration on-site, demonstrating different herbicide programs.