What's Attacking my Strawberries?

To make the proper management decisions, it is important to determine which diseases and nematode species are present.

Major nematode species found in strawberries include sting, northern root-knot, root-lesion and dagger. Diseases such as Fusarium wilt, rhizoctonia and pythium root rot also can cause significant damage. Pre-plant fumigation is an important part of managing many of the following diseases in strawberry fields.

• Northern root-knot nematodes occur in the roots of the plants. They are occasionally present in the roots of strawberries, with the primary symptom of stunting. Other symptoms include unthriftiness, galling, wilting during hot days, chlorosis and suppression of fruit yields.

Progressive decline of strawberries due to sting nematodes                                                  University of Florida

• Sting nematodes are the primary nematode parasite in strawberries in Florida and are native to the sandy soils of the lower coastal plains of southeastern United States. Sting nematodes are found in the roots of the plant and often cause stunting. This pest is of major importance to commercial strawberry production as they can be very damaging to nursery seedlings and transplants.

• Pythium root rot, also known as stunt disease, causes plants to be unable to respond to nitrogen fertilizers, reducing yield in the process. It thrives under cool, wet conditions with excess water and poor drainage generating model conditions. Symptoms include blackened, decaying roots and wilted, yellowed foliage.
  

• Rhizoctonia are fungi that live in the soil and infect strawberry seedlings. Rhizoctonia can infect seedlings before or after plant emergence, resulting in stem lesions found near the soil surface. Lesions can appear red, orange or brown, with older lesions eventually rotting the outer portion of the stem.