During periods of high heat and the corresponding high evapo-transpiration, several unique orchard problems can occur. Most of these are due to fertigation methods which have been widely adopted to increase fertilizer application efficiency. The benefits of fertigation greatly outweigh most negative impacts, but caution must be used as a simple mis-calculation can cause orchard damage. A field call from a grower in late June demonstrated the potential problems that can occur with fertigation. Observations of yellowing leaves, leaf drop, and death of lower limbs raised concerns by the grower and pest control advisor (PCA), prompting an orchard visit. Initial Observations: Upon arriving to the 11th leaf Sonorra/Nonpareil/Carmel (all on Nemaguard) orchard I noticed excessive leaf drop across all varieties (Picture 1). Most of these leaves were coming from the interior of the canopy, suggesting the possibility of drought stress from improper irrigation scheduling. Lower leaves found on the interior of the canopy were burnt back, with a crispy texture. Leaves closest to the trunk that were completely yellow were beginning to abscise, while leaves on the tips of the branches remained green (Picture 2). This is in contrast to lower limb dieback, which causes soft yellow leaves found on the ends of interior branches. Picture 1: Leaf drop associated with the over-application of potassium thiosulfate. Picture 2: Leaf wilting and “dieback” associated with the over-application of potassium thiosulfate. Note how the interior branches are more affected than the branches on the outside edge of the canopy. Up-Close Observations: Close inspection of the leaves revealed a necrotic tip, or burnt region of the leaf. This leaf was surrounded by a yellow halo (Picture 3). Typically, a yellow halo around a necrotic area would suggest the possibility of almond leaf scorch, but due to the widespread occurrence of the problem, this