- Author: Ben Faber
There have been some complaints about satsuma mandarin fruit having problems. These are prone to a rind/skin/peel breakdown when the fruit is not picked promptly. It's not clear what the cause is - wet winter, warm winter - but it is less of a problem if the fruit is picked when it is mature. A lot of the time in southern California, satsumas will develop good flavor and sweetness, but for lack of cool weather, they don't turn bright orange, a hallmark of the fruit. So growers will leave the fruit on longer, hoping for color, but the fruit becomes over mature, and more susceptible to breakdown. This weakening of the peel then opens it up to infection by fungi, such as Alternaria. In warm winters, the peel matures more rapidly and is more susceptible. Early maturing varieties like ‘Okitsuwase' are especially prone to breakdown later in the season, since their rind matures earlier. They end up being a mess, as can be seen in the photo below.
Navels can have a similar problem in these winters with erratic rainfall. Common wisdom is you don't irrigate in the winter, right? Wrong. With no, low and widely spaced rain events, the tree roots dry out, and rewet with rain. Navels are building their sugar in the winter and they become suction balls for water as the sugar increases. The fruit will continue to grow as the tree takes up water. When the roots run out of water, and then are suddenly rewetted during this period, the fruit can suck up water so rapidly that the skin cant expand fast enough and will split. So this is what happens with uneven irrigation or rainfall this time of year. One of those abiotic problems in citrus.
- Author: Sonia Rios
The South American palm weevil has successfully invaded and established in San Diego County where it has killed hundreds of Canary Islands date palms. The weevil is spreading quickly and will likely pose a significant threat to date and ornamental palm producers in the Coachella Valley.
Free Event
Date: March 12, 2018
Location: Coachella Water District, 51501 Tyler St, Coachella, CA 92236
CE and ISA Credits Available
Agenda:
8:00am: Don Hodel, UCCE LA County, will give an overview of palm biology, diseases, and nutrient deficiencies that can be confused with palm weevil damage
8:45am: Tom Perring, UC Riverside, will cover date palm pests
9:30am: Mark Hoddle, UC Riverside, will provide updates on the palm weevil invasion in San Diego County
10:15am: BREAK – Sponsored by the California Date Commission
10:45am: Mike Palat, West Coast Arborists, will review issues that need consideration when removing palm trees killed by palm weevils
11:00am: Ricardo Aguilar, Aguilar Plant Care, will discuss potential chemical control options for palm weevils in infested areas
11:15am: Agenor Mafra-Neto, ISCATech, will discuss new technologies that are commercially
available for controlling palm weevils 12:00pm: Meeting Adjourns
Register for the Meeting Here: http://ucanr.edu/survey/survey.cfm?surveynumber=22821
- Author: Ben Faber
Something hit the citrus trees of Riverside in late December 2017. Some vandal spraying herbicide? It was too widespread. It was all over town, orchards and backyards. It was on the north and east sides of trees. It didn't happen in Ventura or Santa Barbara. It probably happened to a lot of other plant species, but our correspondent had eyes only for citrus.
It sure looks like it could have been a cold, freezing wind, but on closer consultation with our Citrus Specialist, Peggy Mauk who also directs the Agricultural Operations at UC Riverside – it was the demon wind. The Satan Wind. The Santa Ana that dried out the trees that had not gotten sufficient water to cool themselves and had dried out on the windward side of the tree and orchard. Burned, in effect. This is the side of the orchard that dries out the most. It's what's called the “clothes line” effect. The margins that dry first because of the greater exposure to wind, sun and usually lower humidity. In this case, way lower. And by the time the damage was noticed a week later, the winds had been forgotten. Expect more water stress in our future.
- Author: Ben Faber
The avocado trees look terrible and it happened all of a sudden. Well not really, but we have had a warm winter and in the right spots, the trees are beginning to baalllooon with flowers. They look kinda ragged at this time, even when they are in good health. Add a little bit of Persea mite damage to a young tree, with some leaf drop, a little bit of root rot and they look a bit haggard. This is a hopeful time, when you can start expecting to see some fruit set and possible prospects for good yields. Make sure they are getting the water they need, that their roots are in good health and maybe a little bit of nitrogen depending on the fall leaf analysis.
Photos: top to bottom
Persea mite colonies on underside of leaf
Persea mite damage on top of leaf surface
Droopy canopy with persea mite damage, a touch of root rot and stress of flowering
- Author: Ben Faber
Where sufficient habitat is available, wild native bee species often provide all of the pollination services needed for high crop yields and fruit quality. Depending on the species, native bees may nest in underground tunnels, hollow plant stems, and tunnels in wood. Bumble bee colonies favor small cavities under lodged grass, in abandoned rodent burrows, in trees, or old bird nests. These unmanaged pollinators are an on-site natural resource, and unlike honey bees, cannot be moved from the field when pesticides are used. In fact, many ground-nesting species, such as squash bees, long-horned bees, mining bees, and sweat bees, construct their nests in the midst of annual and perennial crop fields. To protect these bees, ensure that drifting pesticides never contact adjacent habitat, even when crops or wildflowers are not in bloom. Scout crop fields, and protect ground nests of solitary bees and bumble bees from insecticide spray. Learn more about managing pesticides and protecting bees at:
UC-IPM: http://www2.ipm.ucanr.edu/beeprecaution/
Oregon State University Extension: https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/pnw591.pdf
Xerces Society: www.xerces.org/
Bee Book: http://www.helpabee.org/