Pros and Cons of Earlier, Warmer Spring

A few discussions this week around an “earlier” than normal year for insects and nut development.

We are somewhere around 10-12 weeks post bloom in the Northern San Joaquin Valley. Nut developing is progressing as expected. We have experienced higher than normal temperatures during stage one of growth which may lead to sizing issues – especially in later blooming varieties (i.e. ‘Fritz’) – similar to what we saw in 2013. Endosperm development should begin or has begun in most ‘Nonpareil’ and pollinator orchards. I suspect that kernel fill will be earlier, leading to an earlier ripening/hull-split/harvest timing.

There are potential benefits from an earlier bloom/development and warmer than normal temperatures. These include earlier shell hardening, which would reduce the risk of leaf-footed plant bug damage. Later infections of bacterial spot may not cause as much crop loss since the fruit size will be larger, more mature. Finally, an earlier than normal harvest would help if it the predictions for an El Nino year come true.

Never-the-less, there are concerns with this type of weather. Based on Joel Siegel’s work of modeling navel orangeworm with degree days from January 1st, we are in “uncharted territory.” Based on data shared on April 10th, we have accumulated 33% more degree days in most areas of the San Joaquin Valley than in 2013, nearly 50% more than in 2012. High egg-laying activity has been reported and experienced in Merced County, which is about a month earlier than a “normal” year. Poorly sanitized, or orchards located next to poorly sanitized almonds, pistachios, or walnuts will have higher-than-normal NOW pressure in 2014. Hopefully, an earlier than normal harvest occurs, which will help reduce damage.

Peach twig borer and codling moth biofixes have also been reported earlier than normal. Trap catches were thrown off a bit by the week of rain, but now seems that traps are active again. Spray timings for these pests will be earlier than “normal.”

Although in pistachio, but related, Bob Beede, emeritus UCCE advisor, has provided some thoughts on chilling and pistachio bloom. I think there is roll-over between the observations in pistachio and the earlier bloom issues in almond – which may be explained by inadequate winter chilling.

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2 thoughts on “Pros and Cons of Earlier, Warmer Spring

  1. Hi David,
    Do you use a growing day degree model to forcast fruit or kernel size and harvest date.?
    Last spring here in Australia, in the stonefruit growing areas, we also had an excetionsally warm and dry spring, with the result of early harvest but the main problem was in smaller and softer fruit.
    There is a model for GDD in peach,We found this valuable for indicating harvest date, so crop load and inputs can be adjusted.
    Is there a model relevant for almonds?



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