A farm call in early April yielded a problem that proved to be difficult to diagnose due to complicating factors. The orchard was three years old with three varieties planted on nemaguard rootstock: 50% Nonpareil, and two pollinators Monterrey (25%) and Avalon (25%). The soil was loamy sand to sand, very coarse, and a hardpan was present. Tree sites were backhoed before planting to remove the hardpan within the tree site. The previous cropping cycle was almond, but methyl bromide was used to fumigate the soil to kill nematodes, soil pathogens, and weeds. Irrigation is by moveable sprinklers. Initial Observations:Overall the orchard has variable growth overall. Some trees are large, some trees are smaller. Branches in the top of the tree have sparse growth. This growth, however, seems to be limited to one variety – the nonpareil. The symptoms are therefore found in every other row. Photo 1 shows the symptoms of sparse growth in the upper trees of one row. Photo 1: Overview of the orchard showing symptoms. Note that the symptoms are more severe on one row of trees. Up-Close Observations:Sparse tree growth has tufts f leaves that are “bootstrapped.” Leaves are deformed are have not completely formed physiologically. Photos 2 shows a symptomatic tree and photo 3 shows a close up of effected leaves. Photo 2: An individual tree showing symptoms of poor leaf growth and development. Photo 3: An isolated branch showing “bootstrapped” leaves. Possible causes:Glyphosate (Herbicide) damage (Round-up)Dormant applications of chloropyrifos (insecticide) (Lorsban)Zinc Deficiency Diagnosing:The applications of chloropyrifos, a broad spectrum insecticide, can sometimes lead to similar growth responses in almond when applied in the delayed dormant stage. Questioning of the grower yielded that no chloropyrifos was used within the orchard – in fact, he doesn’t use chloropyrifos in any of his orchards. Good –