David Doll0 commentsMay 8, 2015General

2015 Mid-Spring Updates

A lot of excitement this past week with the passing storms. Some large thunderstorms passed through Merced Co. dropping some hail and rain. As with any thunderstorms, rainfall totals vary. A few calls have yielded some concerns which are highlighted below. 1. Irrigation for areas with low rainfall totals will most likely still be needed. Use is highly variable depending on the weather, but for the most part, a warm (>80F) sunny day will require 0.25″ of water/acre to maintain full irrigation for a mature block. Cloud cover and cooler temperatures can reduce demand by as much as 1/2. This is using an assumed Kc value of 1.00. 2. Ants. Fields should be scouted and, if needed, baits should be applied. Baits – since they are growth regulators- must be applied 1 month prior to harvest for maximum effectiveness.  Be mindful that not all ants present within the orchard feed on almonds. A quick trick to distinguish “good ants” from “bad ants” is to throw potato chips or a hot dog near the mound. If consumed, it can be assumed that the colony will also feed on almond kernels. Another trick is to  stomp near the mound to bring ants to the surface. If they swarm out of the mound, are red in color with a black butt and bite, they are mostly likely fire ants. Monitoring and treatment information can be found on this previous post and at the UC IPM Website . Ants often cause more damage than expected. High populations can consume between 1-2% of the crop within four days. 3. Hail damage. Hail can cause crop loss as it knocks nuts and new growth form the trees. Nuts that are “bruised” may fall 3-5 days after the damage occurred. If the nut remains on the tree, it will typically yield

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David Doll0 commentsApril 6, 2015General

Mid-Spring Considerations/Update

The 2015 almond season is in full swing. Many orchards have went through their drop, fertilizer applications and irrigation have began, and pest management concerns are beginning to form. Below are some thoughts and considerations from recent field visits. 1. Crop development is ahead of schedule – by as much as a month. Kernel fill is beginning in many ‘Nonpareil’ orchards, meaning that ‘Butte’/’Padre’ orchards won’t be far behind. This timing is important as about 80% of the season’s nitrogen budget should be applied prior to kernel fill – which may occur as early as early May! Secondly, it indicates that at this point – “What you see is what you’ll maximally get” in regards to kernel size, and farming practices – more particularly irrigation practices – can only reduce crop size. 2. Peach Twig Borer’s (PTB) “May Spray” timing looks to be an April timing. In the Merced area, our traps picked up a biofix around March 15th, which means we will be approaching 300 DD in about 7-10 days. Keep in mind that the spring spray timing for PTB is 300-400 degree days after the biofix. It may also be possible for the May Spray to have some effect on NOW.  Frank Zalom (UC Davis Entomologist) has found through research trials that timing the spray to 100 DD post NOW biofix (egg traps) and around 400 DD post PTB biofix can provide good control of NOW and PTB at harvest. 3. Rain is predicted for Tuesday (the 7th). Hopefully some rain will fall in the valley to help with the multitude of water issues. This rain may also bring some potential for fungal disease – especially rust and scab. Consider an application if there has been a history of disease. This application can be made 1-2 days after the rain event and

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David Doll5 CommentsJune 7, 2014Horticulture, Irrigation

Water Stress, Early Hullsplit, and Kernel Size

I have been getting a few reports of hull-split in almonds from varying points across the state. We were expecting an earlier than normal hull-split, but many would agree that this is earlier than expected. Much of the splitting trees are in the more stressed areas of the fields, or in orchards with reduced water allocations. Although I haven’t observed this until this season, early hullsplit induced by spring-time water stress has been described in the literature.

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