- Author: Ben Faber
Research to help plant growers
protect bees and manage pests.
A group of scientists from the IR-4 Project is doing research to explore the relationships between bees, environmental horticulture plants, and pesticides. This group has put together a database allowing users to create customized plant lists for bees, to research articles, to find pollinator news updates and to research best management practices documents. Check it out:
https://protectingbees.njaes.rutgers.edu/
The research is primarily targeted towards helping environmental horticulture growers, but the information should also produce valuable resources for home gardeners or anyone interested in the interplay between bees, plants, and pesticides.
This website is their hub to:
- Share our research and updates
- Provide customized plant lists to help gardeners
- Provide resources to plant growers
- Share related pollinator information and news
- Author: Ben Faber
World Bee Day
https://www.un.org/en/events/beeday/
And more things to learn in this slide set
https://www.slideshare.net/sdroege/25-facts-about-wild-bees-in-north-america
- Author: Ben Faber
Avocado is a neotropic tree which has been commercialized world-wide, yet it's native pollinators have been little studied. The most frequently studied pollinator has been the old-world insect, Apis mellifera. In commercial orchards it is common practice to introduce honey bee colonies, although it is not clear exactly what the extent of their effect is in California orchards in the presents of native bees and other pollinators. The purpose of this study is to evaluate the range of avocado flower visitors and to assess whether those numbers can be affected by the introduction of gardens that might promote their numbers in the orchards during the avocado bloom period.
Measuring pollinator performance is difficult because of weather impacts, alternate bearing habit and the high level of fruit shedding in avocado. In this study, pollination gardens have been established in three avocado orchards in coastal California near Santa Barbara, just north of Los Angeles. These gardens have been established since 2014 with a variety of perennials that can supply nectar and pollen over the year and especially during the prolonged flower season. The three orchards where the gardens are established each exceed 40 ha. Gardens have been established in just one portion of the orchards, so that flower visitation can be assessed near and far from the gardens. The individual visitation activity of flower visitors was evaluated per unit time and their abundance on avocado flowers near the gardens and away from the gardens. Visitation was also similarly assessed on the pollinator gardens. Pan traps were also used to assess the presence of native bees in the orchards.
The most abundant visitors in all years have been Syrphid spp. along with a variety of other flies and wasps. The most abundant native bee species have included Ceratina, Halictus, Agapostemon and several andrenid species. The highest diversity and abundance of visitors has occurred after the high rainfall year of 2016/17 after previous drought years.
Read more at:
http://ceventura.ucanr.edu/newsletters/Topics_in_Subtropics76791.pdf
- Author: Ben Faber
I recently came across a library of all kinds of images of pests, diseases and crops. It has lots of entries, such as “Bees of the United States”:
https://www.ipmimages.org/browse/projectsubject.cfm?proj=1154
Alkali bee
And images of citrus pests and diseases and even different cultivars of citrus, under “Citrus ID”:
https://www.ipmimages.org/browse/projectsubject.cfm?proj=108
'Xie Shan" citrus cultivar
And even a few avocado images:
https://www.ipmimages.org/browse/Areathumb.cfm?area=277
But there's a heck of a lot more.
Clicking on the different links and their volumes of images will take some time because of the shear number. The images have been collected as a public data base for not only academics, but also for the general public. At present, it's not too easy to search, but it's worth a look.
Here's a list of the different categories that can be perused:
Commodity Groups
Grain Sorghum and Small Grains
Grain Sorghum and Small Grains
Plant Pathogen and Microbe Culture Images
Forestry, Wildlife and Natural Resources
Taxonomy
Biological Controls
Damage Types
Insects
Bark Beetles and Phloem Feeders
Seed, Cone, Flower, Bud and Fruit Damaging Insects
Diseases
Parasitic and Epiphytic Plants
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- Author: Sonia Rios
Avocado trees can appear completely covered with flowers. A typical full grown healthy avocado tree in California can produce up to a million flowers a year, but, on the average, fewer than 200 flowers per tree will set fruit that will hold and develop to maturity and harvest (about 10,000 lbs/acre, or less). Upon occasion, we have seen some groves with trees setting an average of 500 flowers per tree (25,000 lbs/acre), but this is rare. More commonly, only 100 flowers (or less) per tree will set and hold fruit to maturity (5,000 lbs/acre or less), much to the distress of growers (Bender 2013). Flowering is typically spread over six to eight weeks.
The avocado flower has both functional male and female organs. The male floral organ, which produces pollen, is comprised of the anthers and stamens. The female floral organ is comprised of the stigma (which receives the pollen), style and the ovary. The flowers are small (10 mm diameter). The flowers are usually only open for 2–6 hours, then close and open again for 2–6 hours on the second day. When a flower opens for a second time, it produces pollen and the stigma is not receptive. Flowers then close and remain closed. Flowers will usually be one sex in the morning, closed in the middle of the day and the opposite sex in the afternoon. The timing of the sex phases can be quite defined, but environmental conditions will affect the timing and duration of the male and female phases. The mature tree can produce in excess of a million flowers during the flowering period.
Avocado cultivars are classified in two groups (A or B) based upon their flowering behavior. In the type ‘A' cultivars, the female organs are receptive to pollen in the morning and the pollen is released in the afternoon. Unfortunately, most of the currently available "B" varieties are classed as "greenskins", which return less to growers. In the type B'cultivars, the pollen is released in the morning, while the female organs are receptive in the afternoon. Type A cultivars include: Hass, Gwen, Lamb Hass, Pinkerton, Reed, Gem, and Harvest. Type B cultivars include: Bacon, Ettinger, Fuerte, Sharwill, Sir Prize, Walter Hole, Zutano, Marvel and Nobel. Both type. It is believed that the interplanting of complementary flower types can boost fruit set and therefore yield by making pollen available. The separation in time of the male and female phases has led most observers to believe that a vector or "pollinator" is needed to move pollen from one flower to another.
Steps to take to Improve Pollination (Bender 2014):
1. Bring beehives into the grove. The University of California farm advisors have usually recommended 1 – 2 strong hives per acre, but Ish-Am (2000) suggests that 1 hive is rarely sufficient, and in many cases 4 hives are required. California growers usually have to rent hives (in 2002 hive rentals averaged $42 per hive), but sometimes beekeepers will drop a load of 80 hives for free if the grower has good bee forage nearby. Bees should have water available; floating boards on ponds or reservoirs enables them to land and drink without drowning.
2. Add pollinizers to the grove. Ish-Am recommends a pollinizer tree row be located at least every fourth row. Some growers in California use pollinizers as wind-breaks around the grove, and some replace thinned-out trees with pollinizers.
3. Keep the orchard open. Direct sunlight should reach the lower branches of each tree in order for the trees to produce a “wall” of flowers down the ground. In avocado production, this can only be accomplished by pruning the upper branches on a yearly basis. Keeping open channels through the grove encourages the flight of bees.
4. Other types of bees? Bumblebees have been reported to increase yield in avocados in Israel where honeybee populations were low. New World Carniolan bees have been used in an experiment in San Diego County for pollination: results were inconclusive as to whether they increased yield compared to Italian honeybees, but it was found that they gather more nectar from avocado (Fetscher et al. 2000). Work with these bees, and other wild bees, may eventually reveal a more efficient pollinator for avocado.