Jhalendra Rijal1 CommentMarch 22, 2017Insects

Seasonal Insect Pest Monitoring Updates in Almonds

This year has been a challenging year to conduct any winter cultural practices due to constant rainstorms and flood situations. By now, however, mummy nut removal from the trees and ground should have been completed. Orchard sanitation is a very effective cultural method to control navel orangeworm (NOW) in nut crops. Almond mummies not only harbor overwintering larvae (Fig. 1), but also serve as the resource for egg laying (Fig. 2) by NOW females in the spring, during which new nuts are not yet vulnerable to NOW infestation. For insect monitoring in almonds, we already passed the trap placement timing (February 15) for Oriental fruit moth (remember the biofix of OFM was February 16 last year). Put navel orangeworm egg traps out by March 15 (South San Joaquin Valley) or by April 1 (North San Joaquin and Sacramento Valleys). Use black egg traps filled with the almond meal + 10% crude almond oil. Hang the traps at head height on the north side of the Nonpareil tree, at least 5 trees in from the edge. Put one trap per 10 acres with at least 4 traps per orchard. Remember to change the bait frequently as wet and lumpy bait is not effective in attracting females for egg laying. The biofix of NOW egg laying was April 18 last year. Follow the link for the details. Pheromone traps and lures are available to monitor male NOW activity. Although the relationship between egg and pheromone traps has not been fully understood, pheromone trap capture data still helps in making NOW control decision. In the orchard with NOW mating disruption, use of the pheromone trap is strongly recommended to assess whether the mating disruption is working. Negligible to no moth capture is expected if the mating disruption is working properly. For San Jose scale,

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David Doll0 commentsMay 23, 2015Insects

Webspinning Spider Mite Management in Almonds

Written by David Doll (UCCE Merced) and David Haviland (UCCE Kern) As summer approaches almond growers need to be monitoring for webspinning spider mites.  The most common species during the summer are Pacific and twospotted spider mite, though on occasion strawberry spider mite can be found. As adults, all three mites look and behave similarly, even though control of Pacific spider mite is more difficult to control. Webspinning spider mites overwinter in the orchard under rough bark and ground litter. During the spring, usually in March and April, migration will occur from these places into the lower areas of the tree.  These early-season populations are typically small, do not reproduce quickly, and often become prey to early-season natural enemies.   However, as temperatures warm in late May through September, the populations increase rapidly, particularly if natural enemies are absent. In favorable conditions, a lifecycle can be completed in 7-10 days, with 8-10 generations a year. Spider mites damage leaves by sucking cell contents and damage initially appears as a light stippling. As populations increase, mites and their eggs become more visible, and eventually “webs” will appear around spurs and leaves. Leaves with high populations will fall from the tree, reducing carbohydrate production.  If leaf loss becomes severe there is a potential for crop loss the following year. Spider mites are most problematic in orchards that are dusty or where the trees are stressed.  Stressing factors can include insufficient irrigation, nutrient deficiencies, or excessive crop load. The most important factor in spider mite management is biological control.  When natural enemies are abundant, miticides are not needed.  When natural enemies are absent, control with even the best miticides can be short-lived.  The goal is to find a balance that relies primarily on natural enemies supplemented by miticides as needed. The most important predators

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David Doll1 CommentApril 12, 2013Insects

Managing Mites in Almonds with Abamectin

Written By David Haviland, Kern County UCCE Entomology Advisor For more than a decade abamectin has played a key role in mite management programs in California almonds.  When applied properly, early-season abamectin treatments typically provide good mite control through hull split, and in some cases throughout the season.  Unfortunately, recent reductions in the cost of abamectin have led to unnecessary use, and sometimes abuse, of abamectin-based products.  This has led to more and more cases of unsatisfactory mite control at a time when mite management has taken an elevated importance due to increased adoption of pyrethroids for control of navel orangeworm.  This article covers several considerations that should be made while using abamectin to insure that it works effectively and consistently. 

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David Doll2 CommentsJuly 12, 2010Insects

2010 Hull Split time…

I feel that the majority of topics regarding hull split have been discussed in prior entries, so I thought I would briefly make a few points of considerations for 2010: 1). Navel Orange Worm (NOW)/ Peach Twig Borer (PTB): Both insects cause damage to almonds, often NOW damage hiding PTB damage. Both insects are susceptible to the same insecticides. The 2010 treatment window for the 2nd flight of PTB will be overlapping with hullsplit. This is good because we can make one spray for NOW and PTB. This is bad because in years were the 2nd PTB flight occurred during hullsplit, worm damage was higher.  If no PTB treatments have been made and no NOW/PTB treatments are scheduled, I would plan to make one within the coming week. Reduced risk products or pyrethroids will provide control for both worms. Related topics previously covered: Peach Twig Borer, Navel orange worm, and hull split insect management. 2). Apply pesticides slowly – do not exceed 2 MPH with spray rigs. 3). Hull rot: Hopefully nitrogen applications have ended. Plan to reduce water to 80% ET for the coming two weeks. By the last week of July, first week of august, resume full ET. This will help reduce hull rot. Please see the previous article on hull rot. 4). Mites: Haven’t been much of a problem this year, but keep in mind that the use of a pyrethroid at hullsplit will most likely cause a mite flare up by harvest. A miticide should also be applied at hullsplit if a pyrethroid is used. There are a few products available that can knock down high populations of spider mites should a flair up occur. It is critical that these products are applied before webbing appears. 5). Harvest: Hullsplit appears to be a week later this year, suggesting that harvest will be

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David Doll1 CommentJune 27, 2009Insects

Hull Split is Approaching…

Hull split is approaching the the central San Joaquin Valley. In Kern COunty, hullsplit of almonds has been observed on the edges of blocks and tops of the trees, and will progress rapidly from this point forward. Hullsplit is a traditional time of making an application of insecticide to reduce navel orange worm damage and late season mite pressures. Blanks, or unpollinated or aborted fruit, will split first before the rest of the crop. So, as a grower, what do we need to keep in mind during hull split? 1. Insect pest management, which includes Navel Orange Worm and Spider Mites. 2. Water Management to reduce the incidence of hull rot. We will cover point 1 today, and the disease hull rot later this week. 1. Insect Pest Management practices for Hull split. Spider Mites: A miticide will be necessary if a pyrethroid was used within the orchard. Pyrethroids target both spider mites and predator mite populations. Once the predator mites are reduced, the faster reproducing problematic spider mites can flare up, causing tree defoliation. It is essential to include a miticide tank mixed if spraying a pyrethroid. If not using a pyrethroid, scouting the trees can give you an idea if you need to include a miticide. Scouting for mites is simple, should be done in the morning when it is cool, and can give a good idea about the ratio of predator mites to spider mites in your orchard. Please refer to the University of California Integrated Pest Management page for information on how to scout for mites: UC IPM Scouting for Spider Mites. There are several miticides to choose from at hull split. The most commonly used include Acramite, Envidor, Fujimite, Kanemite, Oil, Omite and Zeal. Each of these products can be effective, depending upon populations of

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