2010 Almond Harvest Around the Corner…

Harvest has started in the Southern San Joaquin Valley, and will be starting in the Northern San Joaquin Valley in the coming week. Here are some points to consider for the upcoming harvest:

A few articles posted last year can provide a few tips to help with the decision of harvest timing:
1. Preparing for Harvest.
2. Taking a Harvest Sample for an IPM checkup.

Keep in mind that earlier harvested nuts may have to dry on the ground for 1-2 weeks, while nuts partially dried on the tree will require less time. Nuts that remain in the tree will have a longer period of susceptibility to NOW, while almonds on the ground are susceptible to ants, mold (due to increased humidity), and rain events. A quick orchard walk through looking for fire ants and pavement ants should provide the information needed for this decision.

As soon as the almonds are picked-up, irrigate the trees. Adding a little nitrogen at this point is also advised. It may be possible to water the trees earlier dependent upon the irrigation system. Drip users may be able to irrigate as soon as the trees are shaken, while some micro-sprinklers may have small enough pattern that does not wet wind-rowed nuts.

If stockpiling in the field, cover the almonds with a white tarp – or better yet, a two tarp system that includes a black under layer and a white tarp on top. The white tarp or b/w combo has been shown to reduce stockpile temperature and condensation, helping to reduce the environmental conditions favorable for aflatoxin production. Uncover the piles when possible to prevent the accumulation of moisture underneath the plastic. Fumigation of the stockpiles may be necessary.

If rain is imminent, keeping the almonds in the tree will increase the dry time of the almonds after the harvest.

Hope this helps!

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2 thoughts on “2010 Almond Harvest Around the Corner…

  1. Brad posted the following comment on the Harvest Sample for IPM check up entry. I am reposting it below b/c it contains some oversights that I failed to address in the above article:

    “David, There are a couple items that I would like to bring to your attention. First, although it has been long believed that once almonds were on the ground, they are immune to attack by NOW, recent studies have shown that this is not entirely true. Second, OFM damage can look much like NOW in terms of the depth of feeding in the kernel (I believe this is the correct spelling, rather than kernals)and often looks similar to PTB but deeper.”

  2. Thanks Brad for the comments. Below is a bit of follow up:

    You are correct that NOW damage can occur to almonds that are on the orchard floor. Damage, however, doesn’t appear to be as great as if those same nuts were left in the tree. Thank you for catching my oversight. I may be under-estimating the damage caused by NOW to grounded nuts, but I will try and dig up more info on this subject.

    Usually, early harvesting suggests a longer drying time on the orchard floor. While on the floor, the nuts are susceptible to pests – this includes NOW – but the point I was trying to make in the articles is that ants can be unexpectedly problematic if the population density is high enough. Research has shown that a moderate ant population can inflict a 3.2% rejection rate within 10 days of the almonds being on the ground. This is why it is critical to know the pests and densities present in the orchard.

    The second point about OFM is correct as well. If samples were brought to the office and I was asked to identify if it was either OFM or PTB, I don’t think I would be able to tell you for sure. The other aspect is that PTB and OFM damage is often masked by NOW damage. NOW seems to be “attracted” to the nuts previously damaged by the other worm pests. The reasoning for this is not fully understood, but it may be due to an easier entrance in previously damaged nuts.

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