The first moth to arrive was the alfalfa looper moth, Trichopusia ni. But the most striking: the grape leaffolder, Desmia funeralis. More than...
For centuries, farmers have used all the colors of the rainbow to assess their orchards: The bright pink of blossoms in springtime, the vibrant green of heathy leaves, the red blush on fruit ready to harvest.
However, there are wavelengths beyond what a typical human eye can see that also provide valuable information about the crop – including tree vigor, plant stress, water use and fertilizer needs.
UC Cooperative Extension agricultural engineering advisor Ali Pourreza is peering into these previously invisible colorations to create a virtual orchard that will quickly, easily and inexpensively allow farmers and scientists to manage orchards for optimum production.
To develop his first virtual orchards, Pourreza launched a camera-equipped drone over an orchard at the UC Kearney Agricultural Research and Extension Center in Parlier. As the drone flies over the trees, it snaps thousands of photos and, using photogrammetry and software that stiches the images together, makes a three-dimensional point cloud model of the orchard.
A computer program can make colors that are invisible to the human eye – such as near infrared, red edge and ultraviolet – into imagery that illuminates key crop health indicators. Near infrared indicates the amount of healthy foliage, plant vigor and crop type. If the trees have low near infrared values, it means the plants are under stress. Red edge indicates plant stress and nitrogen content. High red edge values indicate nitrogen stress and low water content in plant tissues.
Patrick Brown, a pomology professor at UC Davis, is planning to use the virtual orchard to map nitrogen use in citrus.
“We are currently working on developing models to help growers determine their fertilization demands and have been contrasting the results from real orchards with the virtual orchard,” Brown said. “We have already utilized the approach to contrast the estimates of tree growth and yield with whole tree excavations and harvests to help validate the virtual approach and provide a more accurate estimate of tree nitrogen demand.”
Ultimately, Brown hopes to develop a way for growers to rapidly and cheaply estimate the nitrogen demand of their orchards, monitor the status of their orchards and manage nitrogen fertilizer applications.
In addition to the color variations brought to light by the virtual orchard, the system provides detailed data on other aspects of the crop development.
“We can learn canopy height and width, the spacing between the trees, total leaf area, canopy density and the amount of shaded area in the orchard,” Poureza said.
This data is of interest to scientists studying plant development, soil health and irrigation.
For example, UCCE agricultural water management specialist Daniele Zaccaria is researching the impact of soil-water salinity on water use by pistachio trees in the San Joaquin Valley.
“In our on-going research study we are characterizing the functional relationships between soil-water salinity, canopy size and density and evapotranspiration of pistachio trees through the light interception by the canopy,” Zaccaria said. “We plan to work with Ali to see how the virtual orchard approach can represent that and simulate the physical process of soil evaporation and tree transpiration as a result of different canopy sizes and densities intercepting different amounts of solar radiation.”
Zaccaria said he also plans to deploy a similar approach to understand how different canopy sizes, planting densities and row orientations found in commercial citrus orchards in the San Joaquin Valley – from navel oranges, to mandarins and lemons – can affect the citrus water demand and use.
In addition to the rich data that scientists can glean from the virtual technology, Pourreza envisions many applications of this technology for farmers, including yield forecasting, blossom mapping, variable pesticide application and robotic harvesting.
UC Davis is the place to "bee" on Sept. 5-8 for the Western Apicultural Society's 40th annual conference, but you'll want to register by Monday, July...
The sweltering summer of 2017 has a silver lining. When the temperature rises above 104, brown marmorated stink bug population growth is significantly slowed, reported Debbie Arrington in the Sacramento Bee.
An invasive pest from Asia, brown marmorated stink bugs showed up in midtown Sacramento in 2013. Their spread to commercial crops has been a concern. The stink bugs feed on dozens of California crops, including apples, pears, cherries, peaches, melons, corn, tomatoes, berries and grapes, said Chuck Ingels, UC Cooperative Extension advisor in Sacramento County. Feeding on fruit creates pock marks and distortions that make the fruit unmarketable. In grapes, berries collapse and rot increases.
In 2014 and 2015, the bugs' numbers continued to rise. In early 2016, Ingels feared a population explosion, but a heat wave in July, with seven days at 100 degrees or higher, plus two days at 104, wiped them out.
“This year, BMSB started off at historic lows (since 2013),” Ingels said. “Then, the June heat wave hit and the population that was there plummeted. Most of our trap counts for the last few weeks have been at or near zero, whereas there's usually a peak in June. So, it seems to be proof that temperatures over 100 for extended periods reduces the population – probably especially eggs and nymphs."
Ingels and UC Davis entomologists are studying the connection between high heat and stink bugs in the lab, where the pest is exposed to extreme temperatures. One hour at 113 degrees killed all the bugs, but mortality was also high over 104 degrees.
Moths, a magnificent microscope (scanning electron microscope) and friendly scientists--what could be better than that? How about free hot chocolate,...