Hull split has arrived for tree nut growers, so it’s helpful for growers to refresh themselves on how best to monitor and respond to hull split. Depending on the variety and location, almonds usually go through hull split in July, while pistachios undergo hull split in August. In almonds, we are already well into hull split this year and approaching harvest, so growers should already be taking measures to promptly and rapidly harvest their crop to avoid NOW. Pistachio growers have a little more wiggle room, but should be monitoring for hull split and considering when to harvest to reduce NOW damage.

When monitoring, growers should keep in mind that hull split does not occur at the same time for all individual nuts in a tree. A common mistake growers make is to only monitor the hull split progress of nuts at eye level. In reality, nuts lower in the tree are usually less mature than nuts higher in the canopy, so growers should be cutting small branches from the top of the tree to monitor the progress of earlier nuts. Different trees in an orchard may also mature more rapidly than others; for example, nuts on the edges of orchards often mature more quickly than nuts on the inside due to the increased exposure to the hot sun.



When reacting to hull split, too early is better than too late. In almonds, hull split spray applications should be made within five days between observing the first almonds splitting. From here, it’s a race against time with NOW. When 95 to 100% of the almonds have split, growers should rapidly harvest their crop to avoid damage from the pest. Almond growers are well into hull split and likely to have already started harvest, but timing is good to keep in mind for next year.

In pistachios, growers will soon face a similar predicament, if they are not already. Individual growers will have to weigh the risk vs. reward of letting a larger proportion of their nuts undergo a natural hull split vs. minimizing the risk of NOW taking advantage of the open nut. Just as with almonds, pistachios should be harvested rapidly and efficiently after hull split.

Monitoring and responding to hull split is critical to ensuring a high-quality, profitable crop. Talk to your GAR Bennett PCA about what IPM strategies can help you and your orchard as hull split comes around, as protecting your crops is particularly important during this critical stage. Technologies such as sprayable mating disruption can provide that extra boost of protection that you need to keep your orchard’s NOW pressure manageable.