At the 2009 Almond Industry Conference, Jim Adaskaveg, UC Riverside plant pathologist, and entomologists Joel Siegel (USDA-ARS), David Haviland (UC Cooperative Extension Kern County) and Frank Zalom (UC Davis), highlighted how newer pest management materials and techniques will benefit almond pest management, expanding the number of options and leading to stable, sustainable pest management programs.
• Almond diseases
In any disease management program, resistance management is a major concern (http://westernfarmpress.com/tree-nut-crops/almond-fungicide-management-0115/index.html). Now that scab resistance to the strobilurin Qol (FRAC resistance group 11) has emerged, a fungicide resistance management program should be followed in historic problem orchards.
For these orchards, Adaskaveg’s research has revealed a two or three-spray program that is highly effective under conditions of high disease pressure. This includes a delayed-dormant spray, which delays and reduces sporulation from overwinter lesions.
This is followed by petal-fall treatments, which also block infection from moving onto the leaves and fruit going into the growing season. For the petal-fall treatments, a number of multi-site fungicides were effective. This included the standard of Ziram. Other fungicides and approaches also worked well, including chorothalonil (various labels). Chlorothalonil currently has a 155 day pre-harvest interval (PHI); a new label is being sought with a 60-day PHI, which would give it flexibility for petal-fall and post-petal-fall applications.
Finally, if needed for historic problem orchards, a number of single-site fungicides — notably sterol inhibitors (SBI, FRAC group 3) such as Quash and Inspire, or premixtures, have been or will soon be registered, and these can be used in rotation with multi-site fungicides. Fungicides applied at this later timing protect leaves and fruit post-petal-fall and on into May, if rains persist. To stave off resistance, it is important that single-site fungicides be applied preventively, not once disease is developing. Be sure to follow the UC guidelines (www.ipm.ucdavis.edu) for efficacy and suggested rotations for resistance management.
Adaskaveg highlighted another disease, Alternaria leaf spot, that has developed resistance to single-site mode of action fungicides when a resistance management/rotation program could not be employed. Recently, this disease developed resistance to strobilurin QoI fungicides (FRAC group 11) and to carboxyanilines (FRAC group 7).
Fortunately, Adaskaveg reported, fungicides in two different resistance groups are being registered and should be available for use against leaf spot this season: Quash fungicide (FRAC group 3) has just been registered, and registration of Inspire, another FRAC Group 3 fungicide, is expected in March. Additionally, registration of Ph-D (polyoxin-D) fungicide, a reduced-risk biopesticide, is expected in March. Ph-D is unique and has been placed in FRAC group 19.
“Rotations of the FRAC Group 19 Ph-D and the Group 3 fungicides (Inspire, Quash) will be highly effective and are welcomed,” Adaskaveg said.
• Insect and mite management
New products and approaches for insect and mite management reported by David Haviland in his presentation give growers a greater opportunity for IPM in almonds than ever before, opening the door for sustainable programs.
Highlights for all-season pest management include reduced-risk products and biocontrol for scale, effective miticides for any time of the season, new insecticides with new modes of action — many with reduced-risk status and showing promise for compatibility with biocontrol agents, the development of mating disruption for navel orangeworm, and the NOW Damage Prediction Tool, which can be found at almondboard.com/NOWPredictor.
During the spring, there are several new options for webspinning mite and insect management. First, several new miticides have come onto the market that fit for mite control any time of the season. Therefore, it is possible to base treatments on monitoring and thresholds, and treat when needed rather than rely on preventive “prophylactic” spring treatments. These monitoring guidelines are outlined on the UC IPM Web site.
New, promising May spray options are also emerging for treatment of both peach twig borer and navel orangeworm, according to Frank Zalom. He reported that in May spray trials last season, a number of these treatments provided good control of peach twig borer strikes and activity against navel orangeworm as measured by mummy nuts which were placed or “seeded’ in the test orchards.
Zalom looked at three different application dates for three insecticides: Intrepid, Delegate, and Altacor.
Because these materials are most active on eggs and newly hatched larvae, he saw the best results with the earliest of the three timings, which were just ahead of the biofixes for both the navel orangeworm and peach twig borer.
The newer chemistries are also being assessed for their impact on beneficial predatory mites. A number of these hold promise as being selective and therefore should not contribute to mite flare-ups, providing another viable treatment option during the season.
For more information on new pest management options, go to almondboard.com.