David Doll2 CommentsApril 17, 2014Horticulture

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.

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David Doll4 CommentsJanuary 14, 2014Horticulture

Almond Dormant Oil Applications and Dry Conditions

There have been several questions over the past two weeks regarding applications of dormant oil onto almonds. Concerns of phyto-toxicity or oil burn have been raised over the dry weather, lack of rain, and lack of moisture within trees. Although the exact conditions that will favor oil burn in almonds is unknown, the following are a few considerations when making this decision.

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David Doll0 commentsFebruary 18, 2013Horticulture

Cold Weather Expected

A cold front is moving into the area this coming week. Even though many areas are still at 5% or less of almond bloom, I thought providing some background information on frost protection and mitigating strategies may be useful if trees are more advanced within your area.

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David Doll0 commentsApril 21, 2012Horticulture

Hail Damage from Last Week’s Storm

Photo 1: Hail damage to a mature orchard.Almonds and leaves litter the floor. I have had a few questions about what to expect from the hail damage experienced during last week’s thunderstorm. I have included a lot of photos as this is, thankfully, a rare event. Crop and leaf loss on mature trees was experienced (Photo 1), and delayed drop of damage nuts should be expected. Nuts that are damaged but do not fall may have kernel darkening at the spot of impact (Photo 2). This may become relevant at harvest grading. If crop loss has occurred on your farm, please contact the local ag commissioner’s office and inform them of the damage for their reports. Photo 2. Hail damage on a developing almond. The sunken spot indicates the point of impact.  Significant damage has been experienced in young trees as well (Photo 3). Trees that have experienced broken branches and tattered leaves should push out new growth. If the growth point of the branch was broken, the bud below the injury should push creating a fork (Photo 4,5). These may, although unlikely, present problems when selecting scaffolds at the end of the first growing year. Consider removing the branches in-season if a bad angle is being developed by a newly pushed scaffold. Photo 3. Damage to a young almond tree.Photo Courtesy of Stephen Boone. Photo 4. Damaged shoot top from hail on first leafalmond. Branch should push new growthfrom below the damaged area.Photo Courtesy of Stephen Boone. Photo 5. Damaged shoot on a first year almond tree. A new branch will push that may create problems at pruning.Photo Courtesy of Stephen Boone.

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David Doll0 commentsMarch 6, 2012Horticulture

Frost Prevention in Almonds

Windy and cold conditions are forecasted for the next few nights. The temperature is expected to drop just below freezing, indicating the possibility of an advection frost. If temperatures stay above 28F, damage should be minimal. Never-the-less, windy conditions will remove heat from the orchard, reducing the effectiveness of frost prevention measures. Here is further information regarding frost damage and control:General Information on Frost Damage PreventionRates of Irrigation to Prevent Damage Basically, application of water via irrigation will increase the heat within the orchard, reducing frost damage. Temperatures will dip to their lowest just before dawn, but irrigation should occur before this time in order to increase heat within the orchard canopy.

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David Doll2 CommentsMay 20, 2011Horticulture

Monterey Drop

Throughout California growers have seen significant drop within their Monterey variety. Discussions this past week within our in-service farm advisor tour concluded that this drop is most likely due to cold damage.Cold temperatures, in the low 30’s, were experienced (and confirmed) in April throughout the Sacramento and San Joaquin Valleys. Although we are not certain, the damage observed appears to be an abiotic (non-disease) issue due to the following evidence:1. Drop has been observed in multiple regions of California,2. Drop was observed in multiple orchards with varying cultural practices,3. Damage in some orchards appears to be in the lower spots,4. Nuts are without disease symptoms of any kind,5. The problem appears physiological. Through the process of elimination, Joe Connell (Butte Co Farm Advisor) began to consider cold damage. Upon looking back at the records, he noted that cold temperatures were experienced for several nights. Since varieties differ in their cold sensitivity, not all varieties were affected. Information regarding the sensitivity of Monterey to cold has not been researched, which leaves the possibility of this variety being more sensitive to other commonly planted varieties (i.e. Nonpareil, Butte, etc.). Connell’s thoughts were supported by observations from Roger Duncan (Stanislaus Co. Farm Advisor). If you are concerned about the drop you are experiencing within your almond orchard, please call your local farm advisor to discuss the various reasons in order to reduce the possibility of re-occurrence.

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David Doll0 commentsMay 14, 2011Diseases

Rain this weekend?

Although a late entry for the week, I figured I better address an issue that is facing many almond growers: a late spring rain storm. A rain event is predicted for Sunday with possible carry-over to Monday. I have received a few calls regarding the decision to spray fungicides for various foliar diseases. In many cases, making an application for a one day rain event is not warranted unless there is a persistent disease problem. Spray applications should be considered if there is a history of almond anthracnose, or in orchards with severe brown rot infestations. If sprays are made, try to use broad spectrum fungicides that target multiple pathways. Using these products will help reduce the formation of resistance. If you do not have a history of these diseases, I would hold off on making an application as the winds and warm weather will usually dry the almond leaves before a severe outbreak occurs. If rust is a concern, Dr. Adaskaveg from UC Riverside has shown that control of almond rust can be achieved even after initial symptom development. He has recommended sprays of sulfur or strobilurins and encourages growers to scout their orchards for the presence of the disease. This is great news since it provides growers with the ability to treat upon seeing an infection versus a prophylactic spray for a disease that may not occur. Keep this in mind as we enter late May and early June – rust symptoms begin to appear in these months.

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David Doll2 CommentsMarch 1, 2011Horticulture

Frost Damage in Almonds

Several calls were received today in regards to the symptoms of frost damage. Temperatures in several areas of California were cold enough to cause damage. Many growers have implemented frost protection strategies, but surveying the orchard still needs to occur in order to determine the amount of damage. Damaged blossoms/almonds will be apparent by dead or darkened tissue. Symptoms will become apparent within 72 hours of the frost event, usually appearing 24-48 hours after the event. When viewing the flowers, looked for water soaked areas that might not have yet turned brown. Symptoms will range, but any damage done to the female parts of the flower will most likely lead to flower abortion/loss. Check all parts of the tree, both at eye level and in the upper canopy in order to determine the extent of crop damage. Since frost damage is an abiotic disorder triggered by the environment, keep in mind the following patterns to help discriminate it from other bloom time issues (i.e.Brown Rot):1). Damage is present over a large area of the orchard,2). Damage is present across varieties – especially if both were in the same bloom stage. This may not be true if one variety is yet to bloom and was in the pink tip stage during the event,3). Damage is associated with known topographical changes, i.e. a low spot,4) Tissue of the blossom is darkened, with no obvious signs of fungal growth. The tree’s sensitivity to frost changes with the various bloom stages. The tree is most tolerant to frost when it is dormant or in pink tip. As the tree begins to bloom, it becomes more sensitive to frosts, with the fertilized flowers or small nutlets being the most susceptible. With fertilized embryos, the jacket may protect the ovary/embryo from damage. Here are some pictures of frost damage:

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David Doll1 CommentOctober 12, 2009Horticulture

Dealing with rain at harvest

A rain at harvest can be expensive – damage to the crop reduces the quality and premiums received from the huller, increase harvest costs reduce profit, and the use of forced air driers are costly. With rain imminent, it is important to keep in mind that practices should be employed to speed the drying of crop, whether it is in the tree or on the ground. The following guidelines may provide some help during a rain event during harvest. If rain is forecasted, do not shake trees as almonds will dry more quickly when hanging on the tree due to increased air circulation. If nuts are already on the ground, blow them away from trees but not into windrows or piles. Doing this will help prevent the nuts from sticking in the mud within the tree row strip. Once the nuts are stuck in the mud, it is difficult to move them away from the trees. Once the rain event has completed, rake the almonds frequently, turning them until they are thoroughly dry. If they are already windrowed, run them through a pickup machine and let the nuts fall out of the back. This will help turn the windrow nuts, increasing air contact, and will help remove wet debris from the pile. A table developed by Larry Reinhart (North State Hulling Company) is provided below to serve as a further guide – especially if showers or high humidity persists. Table 1: Prescribed actions for almond harvest involving a rain event. Information sourced from Chapter 35 of the Almond Production Manual:Connell, J.H., G.S. Sibbett, J.M. Labavitch, and M.W. Freeman. 1996. Chapter 35: Preparing for Harvest. Almond Production Manual. University of California, Division of Agriculture and Natural Resources. Publication 3364. Oakland, CA.

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