David Doll2 CommentsOctober 27, 2014Diseases

Fall Sampling for Nematodes: Now is a Good Time

Late fall is a good time to consider nematode sampling. Sampling may be important to perform if lack of vigor or poor growth is observed within an orchard. Samples should be taken once the soil begins to cool in October. For best results, multiple soil samples should be taken, with a minimum of one sample per soil type present in the orchard. If soils are  relatively uniform,  two to three samples should be made for fields smaller than 60 acres. Five or six samples are needed for  for larger uniform fields. A composite of 5-7 different spots within the soil type or field quadrant should be pooled (mixed and combined) as one “sample.” Soil samples should be taken at a depth of 15″-20″ within the rootzone of the tree. Once enough samples have been collected, they should be placed in a properly labeled bag, kept cool and out of the sun, and submitted to a lab to conduct the nematode analysis. 

Read More
David Doll0 commentsAugust 23, 2013Diseases

Almond Replant Problems: Fumigation Trial Results

BACKGROUND Collaborative trials. More than 10 almond replant trials were established under sponsorship of the USDA-ARS  Pacific Area-Wide Program for Integrated Methyl Bromide Alternatives (PAW-MBA).  The trials were made possible through collaboration and in-kind support from USDA-ARS, UC, UCCE, the Almond Board of California (ABC), TriCal Inc., Cal DPR, growers and many others.  For almonds, initial focus of the PAW-MBA was on fumigant alternatives to MB, which are highlighted in this summary.  More recently, with ABC support, the PAW-MBA program has focused on non-fumigant alternatives, which will be featured (along with fumigant alternatives) in an upcoming issue of the journal California Agriculture (Browne et al.).  

Read More
David Doll2 CommentsOctober 19, 2009Diseases

Sampling for Plant Parasitic Nematodes

Many growers are facing the question of replanting orchard blocks. This aspect of orchard maintenance is critical and essential in maintaining an orchard business. Outside of the general tree removal, soil and ground preparation, there are 3 key biological replant problems that must be taken in consideration when replanting. These include plant parasitic nematodes, aggressive soil pathogens and pests, and replant disease of almond. This blog will focus on the first mentioned aspect of replant problems: nematode sampling and nematode control. In almond production, there are three main parasitic nematodes that are of concern – Ring, Rootknot, and Lesion. Depending upon your soil type, planted rootstock, and previous cropping history, the populations of these nematodes can vary within the soil. It is important to keep in mind that plant parasitic nematode populations are directly related to tree production – in other words, the higher the number present, the more tree damage to expect. A previous blog describes the affect of nematodes on tree growth. Orchard Sampling to Determine Nematode Populations. To determine nematode populations, soil samples collected from the root zone area of a tree should be sent off to a laboratory for processing. In collecting samples, the following procedure should be used: 1. By using a soil map, identify soil texture changes within the orchard block, 2. Time the sampling to occur after the year of cover cropping or fallow period – if one occurred, 3. Attempt to sample from different soil textures and areas of previous tree performance. A good sampling strategy for a 40 acre block can be seen in figure 1. Please note the sampling in different soil textures and random samples throughout the field, 4. Use a soil tube and sample the 4″-16″ depth of the profile – this is the area of most active

Read More