Graduate student Adelaine "Addie" Abrams of the laboratory of Extension agricultural entomologist Ian Grettenberger, assistant professor,  UC Davis Department of Entomology and Nematology, will present her dissertation proposal on "Precision Technologies for Integrative Pest Management of Aphids and Thrips in California Lettuce" at 10:30 a.m., Friday, Feb. 3 in 122 Briggs Hall.

Her dissertation proposal also will be virtual. The Zoom link:
 https://ucdavis.zoom.us/j/99327991233.

 “In the proposed research, I will study the effectiveness of both automated precision spray applications and drone-mediated releases of biological control agents for the suppression of lettuce aphid and western flower thrips in several contexts," she says in her abstract. "I hope that the results of the proposed research will contribute to the development of best-use practices to guide the use of both technologies." 

"I will generate novel data that fill existing knowledge gaps regarding the use of precision insecticide applications and drone releases of natural enemies in lettuce production systems. This will advance the adoption of these new pest management tools and contribute to a more sustainable integrative pest management system for lettuce."  

Addie received her bachelor's degree in molecular environmental biology from UC Berkeley in 2011 and her master's degree in horticulture and agronomy from UC Davis in 2018.  Before enrolling at UC Davis, she worked as a researcher under research chemist Spencer Walse at the USDA Agricultural Research Service (ARS) laboratory in Parlier, CA (2019-2021) and the UC Davis Contained Research Facility in Davis, CA (2012-2019), studying postharvest integrated pest management (IPM) of quarantine pests. 

Active in the Entomological Society of America (ESA), Abrams received a second-place or runner-up award for her student research presentation at the 2022 ESA meeting, a joint meeting of the Entomological Societies of America, Canada, and British Columbia held in Vancouver, B.C., Nov. 13-16.

In her abstract, she noted that "Commercial lettuce production in California's central coast represents 70 percent of the production in the United States. Recent discoveries of some chemistries in ground and surface water in the Salinas valley region have placed the insecticidal chemistries used by the industry at risk of increased regulation. Automated thinner-sprayers use plant-detection sensors to apply chemical sprays directly to individual lettuce plants, so that the same amount of product to plants as a standard broadcast sprayer while potentially reducing the amount of pesticide applied per acre by up to 90 percent. Field experiments testing this technology for the control of western flower thrips (Frankliniella occidentalis) and aphids, lettuce-currant aphid (Nasovonia ribisnigri) and others, were conducted to compare the efficacy of automated sprays to a conventional broadcast application system. Experiments were conducted in conventionally managed organic romaine lettuce fields using a complete randomized block design. Prior to and at regular intervals after treatment, heads were sampled from experimental and control plots to assess pest pressure. Results from this experiment validate the use of the automated sprayers to apply insecticides for the control of aphid and thrips pests in lettuce and will be discussed in the context of developing best-use-practices for this technology."

At the 2019 Pacific Branch of ESA meeting, Abrams delivered a presentation on Rearing methods for brown marmorated stink bug, Halyomorpha halys, on live host plants. She has authored or co-authored several publications on stink bugs.

Graduate student Adelaine "Addie" Abrams of the laboratory of Extension agricultural entomologist Ian Grettenberger, assistant professor,  UC Davis Department of Entomology and Nematology, will present her dissertation proposal on "Precision Technologies for Integrative Pest Management of Aphids and Thrips in California Lettuce " on Friday, Feb. 3.

Her dissertation proposal begins at 10:30 in 122 Briggs Hall and also will be virtual. The Zoom link: https://ucdavis.zoom.us/j/99327991233.

 “In the proposed research, I will study the effectiveness of both automated precision spray applications and drone-mediated releases of biological control agents for the suppression of lettuce aphid and western flower thrips in several contexts," she says in her abstract. "I hope that the results of the proposed research will contribute to the development of best-use practices to guide the use of both technologies." 

"I will generate novel data that fill existing knowledge gaps regarding the use of precision insecticide applications and drone releases of natural enemies in lettuce production systems. This will advance the adoption of these new pest management tools and contribute to a more sustainable integrative pest management system for lettuce."  

Addie received her bachelor's degree in molecular environmental biology from UC Berkeley in 2011 and her master's degree in horticulture and agronomy from UC Davis in 2018.  Before enrolling at UC Davis, she worked as a researcher under research chemist Spencer Walse at the USDA Agricultural Research Service (ARS) laboratory in Parlier, CA (2019-2021) and the UC Davis Contained Research Facility in Davis, CA (2012-2019), studying postharvest integrated pest management (IPM) of quarantine pests. 

Abrams received a second-place or runner-up award for her student research presentation at the 2022 Entomological Society of America (ESA) meeting, a joint meeting of the Entomological Societies of America, Canada, and British Columbia held Nov. 13-16 in Vancouver, B.C.

In her abstract, she noted that "Commercial lettuce production in California's central coast represents 70 percent of the production in the United States. Recent discoveries of some chemistries in ground and surface water in the Salinas valley region have placed the insecticidal chemistries used by the industry at risk of increased regulation. Automated thinner-sprayers use plant-detection sensors to apply chemical sprays directly to individual lettuce plants, so that the same amount of product to plants as a standard broadcast sprayer while potentially reducing the amount of pesticide applied per acre by up to 90 percent. Field experiments testing this technology for the control of western flower thrips (Frankliniella occidentalis) and aphids, lettuce-currant aphid (Nasovonia ribisnigri) and others, were conducted to compare the efficacy of automated sprays to a conventional broadcast application system. Experiments were conducted in conventionally managed organic romaine lettuce fields using a complete randomized block design. Prior to and at regular intervals after treatment, heads were sampled from experimental and control plots to assess pest pressure. Results from this experiment validate the use of the automated sprayers to apply insecticides for the control of aphid and thrips pests in lettuce and will be discussed in the context of developing best-use-practices for this technology."

Abrams delivered a presentation on Rearing methods for brown marmorated stink bug, Halyomorpha halys, on live host plants at the 2019 Pacific Branch of ESA, and has authored or co-authored several publications on stink bugs, including

• Ethyl formate dilution in carbon dioxide for fumigation control of the brown marmorated stink bug Halyomorpha halys, Stål (Hemiptera: Pentatomidae), Pest Management Science, 2022
  
  
• Greenhouse rearing methods for brown marmorated stink bug (Hemiptera: Pentatomidae) on live cowpea plants, Journal of Economic Entomology, 2021 (lead author)

•  Sulfuryl fluoride fumigation to control brown marmorated stink bug (Hempitera: Pentatomidae),Postharvest Biology and Technology, 2020 (lead author)

With spring quickly approaching, many gardeners are dreaming of their garden preparations:  ordering seeds, prepping the soil, cleaning up from last year.  With all these things in mind, have you ever thought about saving the seeds from the crops you grow? There are many benefits in considering this.

• Seeds and plants saved become acclimated to our environment, climate
• There is a greater variety of vegetables to grow
• There may be more genetic diversity when growing old-time veggies
• It is can be cost effective due to higher seed prices

Hybrids vs. Heirlooms

With this in mind, there are some important things to know about what veggies to grow in order to save the seeds. 

There are two major types of seeds:   Hybrid and Heirloom seeds

• Hybrid seeds have been cross pollinated from two different varieties in the same plant species. They are crossed to produce seeds that carry desired characteristics or appearances.
  • Seeds saved from hybrid plants will revert back to their parent plants.
• Heirloom Seeds are non-Hybrid, and open pollinated.
  • Heirloom Seeds are usually more than fifty years old and have been passed down from generation to generation
  • If you plant an Heirloom seed that you have saved from an Heirloom plant, it will grow true to the parent plant.

Spacing plants to prevent cross-pollination

For the seed saving beginner, here is a list of seeds that are easy to save because they are self-pollinating.  However, despite being self-pollinating, it may still be important to space crops for guaranteed purity.  Pollinators can be attracted to the flowers and help with pollination, thus producing offspring with new characteristics. To keep seed varieties ‘pure', using ‘isolation' –planting related varieties at appropriate distance to minimize the chance of crossing.  

How long do seeds last?

This is dependent on the type of seed, but also on how they are taken care of after you save them. To ensure saved seeds will sprout in the future, store them in a cool, dry place away from moisture, heat, and light. 

Common Beans

The seed is the mature bean.  Allow the bean pod to dry on the vine. If growing more than one variety, isolate by at least 20 feet.

• Harvest the dried bean pods and place in a paper bag.
• Dry for a week or more before separating the bean from its pod.
• Grow and harvest from at least 10 plants of the same variety for diversity.  
• Seeds can last up to 4 years.

Eggplant

Allow several fruits from at least 10 plants to ripen far past the edible stage. The skin will become a dark yellow or yellowish-brown color. If growing more than one variety, isolate by at least by 50 feet.

• Mash the pulp by hand as best as you can. The seeds are hard, smooth and plump and won't damage easily.
• Toss seeds and pulp into a bucket of water and stir until pulp separates from the seeds. Seeds will sink.
• Rinse until the water comes out clear. Pour seeds through a screen, spread them in a thin layer and dry for about 3 weeks.
• Seeds can last 3-6 years

Garlic

The clove is the ‘seed', so propagation is achieved by replanting cloves. It is generally agreed that planting the largest cloves will produce the largest bulbs next year. Isolation is not necessary even if growing several varieties.

• After harvest, store garlic at room temperature to prevent premature sprouting.
• Plant from your crop every year.

Lettuce

Seeds are very easy to save.  Allow a dozen plants to grow, unharvested, through the spring and summer.  They will “bolt” (send up seed heads). Isolate by 20 feet if growing more than one variety. Once the seed heads are a yellowing-tan color and very dry, they are ready to save.

• Cut at the stem and place in a paper bag. Once dry, crush the heads and sift to separate the seeds from the chaff.
• Harvest from at least 10 plants of the same variety.
• Seeds can last 2-4 years.

Okra

Pods should be left on the plants until fully mature. Okra is self-pollinating but will cross via bees if two varieties are planted near each other. Plant one variety to ensure purity.

• Pick just as the seeds begin to split.
• Clip and store in paper bag for a few weeks.
• Seeds can last up to 3 years.

Peas

Peas are self-pollinating, however, keep favored plant 20 feet away if growing more than one variety.

• Allow pods to slightly dry on the vine before harvesting.
• When picked, place in a paper bag and allow to dry further for a week or two.
• Thresh them from the pod, and store in a jar or envelope.
• Seeds can last up to 5 years

Peppers

Peppers are very easy to save. Once ripe, it's time to harvest the seeds. Peppers are self-pollinating but will occasionally cross via bees if two varieties are planted near each other. Plant varieties 100 feet away.

• Cut open the ripe fruit, scrape out the seeds and let dry on a paper plate for a week before storing in a jar. 
• Seeds can last up to 2 years.

Tomatoes

Tomatoes are mostly self-pollinating, but to ensure purity, separate the favored plant by 10 feet. Allow the fruit to fully ripen on the stem before harvesting. 

• Cut the tomato open and scoop out the seeds.
• Place the seeds in a jar of water and allow to ferment until a white mold forms on top of the water.
• During this process, cover the top of the jar with paper towel to keep flies out.
• Rinse the contents of the jar with water until it comes out clear.
• Allow seeds to settle between rinses. Good seeds will sink to the bottom each time.
• Spread seeds out on a paper plate and allow to dry for 3-4 days before storing in a paper envelope.
• Seeds can last up to 5 years.
• Watch our Tomato Seed Saving Video at https://www.youtube.com/watch?v=FvTCfcpLQgw&t=1s

Hopefully, these suggestions will inspire you to begin the exciting adventure of saving your own seeds from the crops you grow.  Happy Gardening!!!

Heidi Aufdermaur has been a UCCE Stanislaus County Master Gardener since 2019; Heidi took all photos used in this article.

Resources

California Master Gardener Handbook.

Seeds Matter. www.seedmatters.org

The Heirloom Life Gardener.  Bake Creek Heirloom Seed Company.  Jere and Emilee Gettle.

 

Richard Smith is the Vegetable Crop Production and Weed Science Farm Advisor and Michael Cahn is the Irrigation and Water Resources Farm Advisor. Both are with the University of California Cooperative Extension in Monterey County.

 

Cultural practices for producing lettuce are changing with the development of new technologies and with the advent of new economic pressures. The shortage of labor has spurred development and adoption of technologies that make crop production less labor intensive. The most noticeable and dramatic of these technologies is the development of automated thinners and weeders. These machines are now routinely used in lettuce and other vegetable production (see: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=46608).

Equally important are technologies and practices that make irrigation less labor intensive. The use of permanent solid set sprinkler systems, where lateral pipes are positioned on an unplanted “guest bed,” as well at the use of single-use drip tape both increase the efficiency of labor for irrigation.   Permanent solid-set sprinklers allow growers to cultivate and fertilize crops without needing to remove pipe from the field. Single-use drip tape can be shallowly buried and used to germinate many vegetable crops without the need to install sprinklers. After harvest the tape can be removed using specialized extraction equipment and brought to a recycling facility.

 

Single-use drip for germination of vegetables works well on many soil types where the water can move laterally to wet seedlines six inches or so to the side of the tape (Photo 1). This is a different mode of wetting the soil than sprinkler irrigation where water moves downward into the soil. Kerb (pronamide) is the principal lettuce herbicide and is quite water soluble. This characteristic of Kerb can result in it being moved too deep in light textured soil with heavy irrigations; this can result in poor weed control if Kerb is moved below the depth where weed seeds are germinating (e.g. the top 0.5 inch). In drip germinated lettuce, water moves upwards and laterally which facilitates keeping Kerb in the upper 0.5 inch of soil where it remains more active on germinating weeds.

In drip germinated fields, the label allows for Kerb to be sprayed over the seedlines and then activated with the germination water. The label does not currently allow injecting Kerb into the irrigation water. Corteva is in the process of expanding the Kerb label to allow this application method. In 2021 we conducted an evaluation with a cooperating grower on a site with Mocho loam soil to evaluate the efficacy of Kerb injected in the drip system with the first germination water. Two methods of applying Kerb were tested: 1) the traditional method of spraying the material post planting on the soil surface and incorporating it with sprinkler irrigation (1.5 inches first germination water) and 2) injecting Kerb in the drip irrigation system with the germination water (1.9 inches first germination water). In the drip injection, the Kerb was injected between hours 10 and 11 of a 14 hour irrigation set. The material was injected into a separate manifold from the grower's system to keep it separate (Photo 2). Two rates of Kerb were tested: 3.5 and 5.0 pints/A. Weed counts were made on 19 and 26 days after the first irrigation.

In the first weed evaluation Kerb at both rates significantly reduced the number of purslane plants for each application method compared to the untreated control. There was no difference in the yield in any of the treatments in the sprinkler incorporated treatment, but there was an indication of slight yield reduction in the 5.0 pint/A rate in the drip applied Kerb treatment. These results indicate that injecting Kerb into the drip system during germination of the crop can provide good weed control in lettuce.

These studies help adapt the use of Kerb for a new irrigation technology and helps growers manage weeds better. It is especially important to have low to moderate weed pressure in fields when relying on autoweeders to conduct later weeding operations. Low weed populations help the automated technologies work more efficiently. All of this is to the good to help growers manage costs and to adjust to new realities with less labor to grow labor-intensive crops.