- Author: Sonia Rios
California produces about 90 percent of the nation's avocado crop. California avocado growers compete in both the domestic and international markets with countries with much lower costs of production and labor availability. To stay competitive will require more efficient farming strategies and a significant increase in productivity on the part of California growers, especially with the increase of water costs and labor constraints. To adapt, growers need to dramatically increase yield per acre using the same amount of water or less. Evolving farming practices and new information is essential for growers to stay competitive with the world market.
Since 1995, University of California Cooperative Extension, in collaboration with the California Avocado Society and California Avocado Commission has developed a seminar series to help avocado growers. Each seminar is tailored to each specific growing region in the state: Riverside and San Diego Counties, Central Coast, and northern Central Coast. As part of the educational series, growers and stakeholders are exposed to various topics: economics, pest management, water quality and usage, soil science, pruning techniques, bio-control, Integrated Pest Management, salinity, labor, and harvesting, etc. The audience has a say in what topics will be discussed, and we have had positive feedback in all three locations. Per stakeholder request, round table discussions and field tours have also been incorporated into the program. These seminars have gained a positive reputation amongst growers and continue to impact the industry in a positive manner.
Seminars provide new information that growers share Surveys determined that these seminars address current issues affecting avocado growers in their growing regions and expose them to new skills and knowledge, encouraging change in current cultivation practices. For example, subjects such has high-density plantings, rootstock selection, and salinity management help growers maximize production. In the most recent survey (8/2017), data suggested that as many as 52 percent of the attendees come to the seminars with little to no knowledge on some of the subjects presented and as many as 73 percent of the attendees leave the seminars with either “quite a bit”, or a “complete understanding” of knowledge from the material. In addition, more than 50 percent of the clientele that attended the seminar said they are likely going to share the material learned that day with as many people as possible (10+ people). This assures that the information given is circulating and reaching those who cannot physically attend the meetings. The collected survey information shows a positive outcome and assures the success of the educational seminar series.
Seminars are held January - August of every year - Keep an eye out for next years line up!
- Author: Ben Faber
Recently a grower called up with a beautiful scale that the PCA couldn't identify. I could just marvel at the beauty of it and wondered what in the heck it was. It didn't look like any scale I had seen in the area and others who were queried didn't know either.
I took it into the Ag Commissioner's office and they sent it off to see if it was a new species. Images were sent off to various entomologists and David Haviland in Bakersfield identified it as a Ceroplastes, possibly a Chinese wax scale or Barnacle scale. Others had identified it as Florida wax scale.
It was sent into Paul Rugman-Jones at UC Riverside Entomology for DNA identification. His identification and that of CA Dept of Food and Ag entolomogists came back as Barnacle scale, Ceroplastes cirripediformis.
All of these scales turned out to have been seen in California before, so there was no quarantine issue. It also turned out that all of the adults that were turned in for identification had also been parasitized by some wasp. So there is biological control already in place for it. The issue at stake here, though, is that it's important to be watching for new visitors in the orchard. Joe Morse now retired from UC Riverside Entomology lead a team that intercepted avocados coming into the US. They found a number of scale insects that were new to California and new to the identification world. A number of these scale are parthenogenic, meaning they can reproduce without males, and just one lone female could possible balloon into a massive population in a short time. And on a scale like that, trees would have a hard time without some serious intervention.
- Author: Ben Faber
Last May/June during a hot period and soon after fruit set, avocado growers and PCAs in the Oxnard/Camarillo area were calling in about young fruit about he size of a quarter showing up with white spots. Cutting into the fruit there might only be a small black spot just below the injury. Because that's what it is, a wound response on the part of the fruit to a physical damage. This occurred on several orchards also in the San Luis Obispo area and it seemed to happen in orchards that had recently been sprayed for avocado thrips. No piercing-sucking insects were found at any of these sites. Insects that would feed by feeding on the fruit and causing damage and malformed fruit. Insects that could typically make probing inspections of fruit prior to laying eggs. No eggs or larvae were found in the fruit. Nothing like lygus bug, BMSB, Bagrada bug or other stink bugs was found.
http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=15198
Did it have anything to do with the spray? With the hot weather? With the hot weather and the spray? With the hot weather and the insects that came with it? Did it have anything to do with the hot weather? Did it have anything to do with insects?
And then late June, the calls stopped. No more damaged fruit was being found. And then a lone call from Cayucos. Damage was found on young and older fruit. New damage seemed to be occurring on the fruit that normally sets later in that northern area. The grower walked the orchard and didn't find any bugs. The PCA swept the grove for insects. A yellow sticky card was put out.
So far, no insect has been found on the fruit. So what caused and "is" causing the damage to the fruit? It's not clear. Fruit that was damaged in Oxnard back in late May was tagged to see if it recovered. Ten fruit were flagged and two months later, those tagged fruit were still on the trees. So either the fruit that was attacked fell off with the initial damage or the fruit observed later had healed itself. Fruit have this capacity when they are actively growing to cover over damage. Often it is malformed. In most of cases with this fruit, the damage was very superficial. Occasionally, there deeper pits, but we didn't see any burrowing or tunneling.
If anyone else saw similar damage and has more to offer about this happening, I would be glad to hear about it.
Photos: Damaged fruit that was flagged and observed 2 months later.
- Author: Caio Brunharo and Brad Hanson
Article written by UC Davis PhD student Caio Brunharo from his dissertation research. It was originally posted in the September 2017 "Weed Management Notes" newsletter from the UC Cooperative Extension office in Glenn County by new weed science and agronomy Farm Advisor Mariano Galla (also a UCD PhD student in weed science!).
Take care, Brad
Italian ryegrass management in perennial crops in California
Caio Brunharo1 and Brad Hanson2
1PhD Candidate, UC Davis; 2UCCE Weed Science Specialist, UC Davis.
Italian ryegrass (Lolium perenne L. spp. multiflorum (Lam.)Husnot) causes yield losses in a variety of cropping systems around the world (Figure 1). This species is highly competitive with annual crops but may also compete with perennial crops particularly during the establishment years when they are most vulnerable to direct competition. In orchards and vineyards, ryegrass infestation can also interfere with cultural practices during the bearing years.
Repeated herbicide use has selected Italian ryegrass populations resistant to a variety of herbicide mode of actions across the world. Glyphosate-resistant Italian ryegrass populations were first reported in California in 2008, and the evolution and spread of these populations in the state made alternative postemergence herbicides an important management strategy against this troublesome species.
Recently, poor control of Italian ryegrass with Gramoxone 2.0 SL was reported in a prune orchard near Hamilton City, California. Greenhouse dose-response experiments and field trials were carried out to evaluate Italian ryegrass response to several postemergence and preemergence herbicides.
Our greenhouse studies confirm that the Italian ryegrass population from Hamilton City is resistant to Gramoxone 2.0 SL, Envoy Plus, Roundup PowerMAX and Osprey, whereas Fusilade DX, Rely 280, Simplicity CA, Matrix and Poast controlled both a known-susceptible and resistant Italian ryegrass population (Table 1). (note: Osprey and Simplicity CA, which are not registered in perennial crops, were included in the study for comparison purposes). Our criteria were that whenever the resistance index (RI) was larger than two and the comparison between biotypes was statistically different (P <0.05), the population was considered as resistant to that particular herbicide. Matrix is an exception, however, because this herbicide controlled both biotypes at well below its recommended field rate.
The field experiment with postemergence herbicides corroborates with data from the greenhouse studies, since glyphosate and paraquat did not adequately control the herbicide-resistant population from Hamilton City. On the other hand, most of the treatments containing Rely 280 were effective for control of the resistant population (Figure 2).
From the preemergence herbicide trial, all treatments containing Alion controlled the resistant population up to 150 days after herbicide application. Chateau, Surflan AS, GoalTender, Prowl H2O, and the tankmixes of Chateau + Prowl H2O and Chateau + Surflan AS exhibited control percentages above 90% with long lasting residual activity (up to 150 days after treatment; Table 2).
Even though several postemergence herbicides controlled Italian ryegrass in our research, it should be noted that ryegrass populations resistant to Fusilade DX, Rely 280 and Poast have been reported elsewhere in the state (data not shown), and overreliance on these herbicides will increase the chances of selection of further cases of resistance. A chemical weed management program in areas infested with Italian ryegrass should include a preemergence herbicide with long residual sprayed in the winter (Alion, Chateau, Surflan, GoalTender or Prowl H2O are possible options) tankmixed with an effective postemergence herbicide. In areas where herbicide-resistant weeds are known to be present, alternative herbicide chemistries should be adopted (rather than increasing the herbicide rate sprayed) in both the winter and spring application. In some cases, a short residual grass herbicide included with the post-harvest burndown application may help reduce recruitment of early-germinating Italian ryegrass plants which will reduce weed pressure and densities to be managed later in the season.
- Author: Sonia Rios
Gopher Snakes (Pituophis catenifer), known as a constrictor snake, are one of the most commonly seen snakes in California. Mainly active during the day, they are active after sundown on hot days. They are often observed crawling across trails and roads, especially in the morning and evenings when daytime temperatures are high. They live in diverse habitats and are regularly seen around human residences, including suburban backyards and in agriculture commodities as they are attracted to the rodents which thrive in those areas. The gopher snakes help growers control their pest problems by preying on rodents, rabbits, and birds that would otherwise destroy or ruin crops and yields. When the weather turns hot, they hunt during the night and rest on warm rocks or pavement during the day. They hibernate during the winter and are out and about between April and October, however in Southern California because of the warm climate their presences is more consistent.
Gopher Snakes are large and heavy-bodied reptiles - reported to reach 9 feet (275 cm) in length, but 4 feet (120 cm) is more common. The underside is creamy or yellow, often with dark spots. Unfortunately, this harmless and beneficial species is very often killed out of fear that it is dangerous or that it is a rattlesnake. Since the patterns on their backs are similar to rattlesnakes and because they coil, vibrate their tails, and even strike when threatened. Other differences include: gopher snake tails taper to a thin tip and lack rattles; rattlesnake tails always have rattles (or immature buttons), unless the rattle has broken off, gopher snake heads are usually narrow, while rattlesnake heads are always triangular, and gopher snake eyes have round pupils, while rattlesnake pupils are vertical.
So, if you see a Gopher snake in your grove, its best to leave him alone so that it can contribute to your Integrated Pest Management plan.