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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Kris Tollerup0 commentsMarch 12, 2017Insects

Leaffooted Bug Aggregations Have Begun to Disperse

  Winter temperatures this 2016 / 2017 season were not cold enough to have any negative impact on overwintering populations of leaffooted bug.  Since mid-October we have monitored large populations on a ½ mile-long pomegranate hedgerow in the Parlier area.  Aggregations averaged about 206 individuals on 19 October with just over 50% of the individuals at the 4th and 5th instar stage.  Temperatures remained mild through November and by the month’s end aggregation size averaged ~30 individuals with 16 and 66% of the bugs at the 5th and adult stage respectively.  The decrease in aggregation size likely occurred due to new adults leaving and not adult or nymph mortality.  The temperature did reach a low of 27° F during the early morning hours of 20 December yet no adult or nymph mortality occurred. Our data suggest that female leaffooted bug began laying eggs on the pomegranate during early September and an entire generation was produced by the end of November.  As the temperatures cooled and the pomegranates began losing leaves and the fruit rotted and dropped, essentially all the adults left for more sheltered overwintering sites. In this case, several thousand of those individuals moved to a nearby palm tree and large Cyprus trees. We have closely monitored the aggregations on the Cyprus trees since mid-February and until early-March the aggregations have remained compact consisting of roughly 5 to 40 adults.  Temperatures have now warmed and we are seeing smaller aggregations, greater flight activity, and individuals on nearby citrus trees.  I interpret this increase in leaffooted bug activity as an indicator that the bugs have begun to disperse and will soon move into almond in search of food. Weekly monitoring should begin within the next seven to 10 days through May, and then every one to two weeks through June. 

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David Doll1 CommentJanuary 18, 2016Insects

Bloom Bt for Peach Twig Borer Control

Written by John Edstrom, UCCE Farm Advisor Colusa County, Emeritus Hopefully, the central valley will finally receive drought relief from recent El Niño driven storms. The resulting wet soil conditions, however, can prevent orchard access for many orchard operations including dormant sprays. Without dormant insecticide sprays, peach twig borer (PTB) populations can increase dramatically and threaten next years crop. Worm reject levels were troublesome and costly to many almond growers this past season and point to the need to control PTB. Besides kernel damage, twig borer feeding also kills young buds and shoot tips after bloom and deforms young tree scaffold limb development . Fortunately, growers have a very safe alternative to dormant sprays using Bacillus thuringiensis (or Bt) to control PTB during the bloom season without harmful side effects to applicators or the environment. Other insecticidal materials claim to be safe to bees but may negatively impact bee colony health. Bt has no adverse affects to any stage of honeybees or the health of the hive.  Bt is a natural bacterial based insecticide that is toxic only when ingested by lepidopteran larval stage pests and is completely safe to beneficial predators and parasitoids. Bt is exempt from pesticide use regulations and so is particularly useful near urban or environmentally sensitive areas. The bloom Bt control strategy has proven effective since its was developed in the 1990s during a time when regulations were restricting the use of the highly toxic organophosphate spray materials. Bt is a perfect fit for almond IPM programs. Its only down side is that multiple applications are needed for complete control. Fortunately, Bt products are inexpensive and can be tank mixed with fungicides applied for blossom and leaf diseases around bloom, so the total costs are comparable or less than standard insecticides. Generally, two sprays are

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Jhalendra Rijal0 commentsDecember 22, 2015Insects

Role of Winter Sanitation for Navel Orangeworm Management

Written by: Jhalendra Rijal, Area IPM Advisor, UC-Cooperative Extension (San Joaquin, Stanislaus, Merced) Navel Orangeworm (NOW) is a primary pest of almonds, pistachios, and walnuts, with other significant crops hosts such as fig, citrus, pomegranates. This pest was first introduced in southern California in 1942 potentially from Central and/or South America. Because of the wide host range, this pest was quickly spread to the entire Central Valley within 5-7 years of its first introduction, established and had become a major production threat in almond and other nut crop production. Adults are greyish-brown moths (about ½ inch long) with grey markings on wings. Eggs are laid in mummy nuts or in the nuts with initiation of hull-split. Tiny first instar larvae bore into the nutmeat and all stages of larva feed on nuts producing large amount of webbing and feces (i.e. frass). Larvae are white to pink with a reddish-brown head, and with a typical crescent-shaped markings on the second segment of the body just behind the head. The mature larvae (5th instar) can grow upto ¾ inch in size. Besides direct damage on nuts, NOW larval damage can lead to fungal infections, such as the mold that produces aflatoxin, known to cause carcinogenic and mutagenic effects on human. The larvae overwintered in mummy nuts that are in trees or on the ground. Among non-chemical ways of reducing NOW populations or damage include early harvest and winter mummy removal (i.e. sanitation).  Winter Sanitation of orchards during the winter is the most effective way to reduce the damage in upcoming season. Mummy nuts should be removed from the trees before bud swelling stage (late January/early Feb.) by shaking the trees or by hand polling. The nuts should then be destroyed on the orchard floor by discing or flail mowing by March 15. UC IPM

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Franz Niederholzer0 commentsDecember 19, 2013Horticulture, Insects

Pruning Can Improve Pest Control

A replicated field trial in mature Non-pareil almonds at hull split using a diamide insecticide (Altacor®) measured better navel orange worm (NOW) control in the tops of pruned vs unpruned trees.  As regulatory and/or resistance issues with key pests (navel orange worm, alternaria, etc.) move the almond industry towards selective pesticides that require excellent coverage to deliver effective pest control, growers may want to review pruning options for young and mature trees with an eye to improving spray coverage in the upper tree canopy.    

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David Doll3 CommentsApril 27, 2013Insects

NOW Biolure – 2 Different Moths in Trap

I have been hearing multiple reports of high counts of Navel Orangeworm (NOW) moths trapped with the new Suterra Biolure. We have placed our traps and have had high trap counts as well. In our liners, however, we have found two different moths – one being NOW  (Amyelois transitella) and the other being a meal moth (Pyralis farinalis). Both of these moths are within the same family (Pyralidae) and can be confused. 

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David Doll0 commentsMarch 23, 2013Insects

New video for managing almond pests using the year-round IPM program

Not sure what you should be doing to manage pests for the upcoming season?  Check out the year-round IPM program for almonds on the UC IPM web site. Need help using it?  UC IPM has just published an online video to help you manage almond pests using the year-round program. How to Manage Almond Pests Using the Year-Round IPM Program is a narrated how–to guide written for growers, PCAs, and others who work in almonds, showing what needs to be done throughout the season to stay on top of pest problems.

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David Doll1 CommentMay 2, 2010Insects

Managing Orchard Ants – time to scout for activity!

Pavement and Fire ants can cause significant damage to the almond crop. Feeding throughout the year on seeds of grasses and broadleaves, ants are only problematic once the almonds are shaken to the ground. Ants can completely hollow out the nut, leaving only the pellicle behind. Damage increases the longer the almonds are on the ground. Within the San Joaquin Valley, the southern fire ant has a wider distribution and usually causes more damage than the pavement ant. Pavement ants are found in the northern San Joaquin Valley and into the Sacramento Valley. Within Merced County, we have both the Southern Fire Ant and the Pavement Ant. Recently, Merced County has had infestations of the Red Imported Fire Ant (RIFA), a third problematic ant for almond growers, requiring quarantine actions to control this invasive pest. Please see Guide to Identifying Orchard Ants to help identify ants. Ants tend to be problematic on drip or sprinkler irrigated orchards. Within flood irrigated blocks, ants are limited to tree berms. Moist, cool temperatures increase above ground activity of ants; hot temperatures drive the ants deeper into the colony. Varieties with a tight shell seal are more resistant to ant damage, or with shell splits less than 0.03 inches wide. Shell seal can vary greatly year to year depending on crop load, nut size, and horticultural practices. The orchard should be surveyed for ant colonies 2-3 days after an irrigation in the months of April – May in order to determine if a treatment is needed. Once the temperatures increase, problematic ant surface activity decreases, giving an inaccurate count of the population. In scouting for ants to determine if treatment is necessary, choose five survey areas per orchard, each about 1000 sq. ft., including the soil area from mid-alley to mid-alley beneath trees. Count the number

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