For at least the past decade, an unusual decline of black walnut (Juglans nigra) has been observed in several western states. Initial symptoms involve a yellowing and thinning of the upper crown, which progresses to include death of progressively larger branches (Figure 1). During the final stages large areas of foliage may rapidly wilt. Trees often are killed within three years after initial s...

Intercropping arable crops in orchards is a sustainable land use for intensifying agricultural production, under the condition of plants’ complementarity sharing resources. This study investigated aspects water and yields intercropped systems walnut crops. To assess possible temporal between trees, summer crop—buckwheat—and winter crop—barley—were orchards. The productivity were studied two des...

The Guthion-resistant strain of walnut aphid parasite, Trio x y s p a II i d us. was mass reared in the greenhouse on potted walnut trees and released into five commercial walnut blocks near Colusa, Stockton, Modesto, and Hanford. Parasites successfully established in four of the five sites, surviving on field rates of Guthion and Supracide. The Guthion-resistant strain persisted in the release...

Anthracnose is one of the most common and important foliage diseases of shade trees in Iowa. Symptoms of anthracnose are often referred to as “leaf blights” or “leaf spots” and are most serious on sycamore, ash, maple, white and bur oak, and walnut. Linden, hickory, elm, red and black oak, and other deciduous trees also are susceptible, although anthracnose is less common and damaging on these ...

Anthracnose is one of the most common and important foliage diseases of shade trees in Iowa. Symptoms of anthracnose are often referred to as “leaf blights” or “leaf spots” and are most serious on sycamore, ash, maple, white and bur oak, and walnut. Linden, hickory, elm, red and black oak, and other deciduous trees also are susceptible, although anthracnose is less common and damaging on these ...