nov-dec-2020

IN YOUR ORCHARD recommendation is a post-sanitation target of 0.2 mummies per tree and eight mummies on the ground under a tree. This recommendation was developed in 2003–2006 when NOW pressure was generally greater in the southern San Joaquin Valley than in other regions and has not been repeated in more northern districts. However, in the last decade, central and northern almond growing regions have seen growing NOW pressure/damage. Growers in those areas should consult with their PCAs regarding the target mummy count after sanitation. If it is a warm, drier-than-average winter as forecast, buds may push earlier and sanitation may need to be finished sooner (by late January) to avoid excessive bud loss. Watch the buds, not the calendar, to decide when to stop shaking and/or polling. Winter weed control is an important part of year-round orchard floor management. The degree of weed control using herbicides varies with weeds present and herbicide(s) used. For the best weed control, survey your orchard ahead of herbicide selection and spraying. Pre-emergent herbicides offer long lasting weed control compared to post-emergent (“burndown”) herbicides with fewer applications. Bare soil and incorporation with a small amount (0.25 to 0.5 inches) of water (rain or irrigation) are needed for best weed control. Large storms with high rainfall totals are not good for herbicide efficacy as inches of water following spraying can push some amounts of certain herbicides down in the root-zone and below the area near the soil surface where most weeds are found (and controlled with pre-emergent materials). Small rainfall or irrigation events (0.25 to 0.5 inches) move the herbicide into the soil where it is fixed and not affected by any large rainfall events. Longer lasting weed control with the same rate per acre of pre-emergent herbicides can be achieved by changing how the product is used. In recent research by Dr. Brad Hanson and his lab, sequential applications (December and March) of two lower doses of an herbicide produced longer weed control than the same total rate per acre applied once in December. This overall strategy may help reduce costs while delivering excellent weed control. If planting an orchard this winter or spring, consider using a pre-emergent herbicide to help manage weeds in the first season. Weeds compete with young trees for water and nutrients and controlling weeds in the first year is challenging with post-emergent herbicides due to herbicide resistance, label limitations, tree damage risk and the cost of repeat applications needed for long-term weed control. Only a handful of pre-emergent herbicides are labeled for use in the first leaf. Check with your PCA regarding materials, rates and timings and always read the label ahead of application. Gophers can kill almond trees and are active 365 days a year. Manage gopher populations with at least two control strategies (fumigation and trapping, fumigation and bait, etc.) year round, but especially in the winter to limit the jump in gopher numbers following the late winter breeding season. Better gopher control is achieved when workers are trained in trapping and baiting. Pruning Pruning young almonds, especially those in their first and second dormant season, is particularly important to orchard success. Careful scaffold selection, with attention to spacing around and up and down the trunk as well as branch angles, is critical to supporting large crops while limiting the chances for scaffolds to tear out in high wind and/or heavy crop load. First dormant pruning of summer planted, potted trees can be a challenge; especially those on vigorous rootstocks. To drive overall tree growth, potted trees planted late are often not pruned, despite the often ugly group of multiple shoots clustered at the top of the trunk. When the winter arrives, the tree trunks are thicker, shoots have extended and the root system has expanded but the branch angles are still ugly. Cutting the shoots back to the trunk — leaving the tree looking like a newly planted, pruned bareroot tree — is an important step in establishing good, sound tree structure. In my experience, the trees grow strongly in 4 6 A L M O N D F A C T S