Fighting in the Dirt

For eons farmers have battled two things – pests and the weather. While we still can’t control the weather, we can fight pests that target our crops, whether in agricultural fields or our own back yards.

For the past decades, farmers have primarily relied on pesticides, but we now know that many of these chemicals are toxic and pests develop resistance to them. There is a high demand to find effective and safe options to traditional pesticides, especially for organic farming.

Enter WCAHS new investigator, Dr. Chris Simmons, who is working on such an alternative. It’s called biosolarization. Think of it this way, biosolarization simply means harvesting the power of biology (bio) plus the sun (sol) to kill pests. Add plastic and compost, and you are ready to roll.img5902p87

Well, it’s not quite that easy. Simmons is specifically studying how to use biosolarization to replace fumigants, toxic gases that are pumped into the ground under the cover of heavy plastic tarps, to kill soil pests before planting. You many have seen this done in fields with rows of plastic. While fumigants work quickly against pests, they are essentially nerve gases that can cause serious injury and even death when inhaled by farmworkers or nearby communities if not used correctly.

In place of adding fumigants to the soil, Simmons adds compost and leftover skins and seeds from grape or tomato processing, wets the soil, and then covers it with plastic tarps to let biosolarization do its work. Heat from the sun becomes trapped under the tarp, encouraging heat-loving bacteria to grow, making the soil more acidic, which along with the high soil temperature helps eliminate pests like weed seeds, insects, worms, and many fungal and bacterial pests. Simmons is optimizing this process (timing, compost to use) for specific California crops grown in the Central and Imperial Valleys.

While the science of biosolarization is still evolving, there is no reason why we can’t use its cousin, solarization in our own garden. Solarization is just biosolarization minus the “bio” part – you don’t need to add specific compost to the soil. Instead you just tightly cover the heavily wetted soil with plastic during a hot, sunny time of the year. This will trap the heat of the sun to kill garden soil pests. In addition, your soil may become more nutrient rich as the heat breaks down organic matter.

You can do this easy, inexpensive project in a day and be rewarded in 4-6 weeks with a healthier garden.

Solarize Your Garden in 5 Simple Steps



Step 1. Get rid of any dead plants and other debris in your soil by hand picking or raking them away.

Step 2. Smooth the soil surface so that it is level.

Step 3. Water the soil so that it is wet up at least 1 foot deep.

Step 4. Place a clear plastic tarp on top of the soil. Plastic sheeting or plastic “drop cloths” for painting are readily available at hardware stores. Secure the edges of the tarp with soil.

Step 5. Remove the tarp after 4 to 6 weeks­ and begin gardening.

To see a more detailed demonstration of garden bed solarization, check out Alabama Cooperative Extension System Regional Agents James Miles and Mike McQueen in this video.


Occupational Hazards and Climate — NIOSH Science Blog

Climate-related occupational hazards have historically received little attention. In 2009, NIOSH began work to address this gap and developed a framework to identify climate-related occupational hazards. Recently, NIOSH investigators published new work in the Journal of Occupational and Environmental Hygiene. Based on a review and assessment of the peer-reviewed literature from 2008–2014, the article updates…

via Occupational Hazards and Climate — NIOSH Science Blog

Protect Yourself with Integrated Pest Management

If there is one thing that hasn’t changed through the centuries, it’s the battle between pests and farmers. Stories of whole crops being decimated in the blink of eye are recorded in every culture.

Today, there are incredible resources to help with this age-old problem, including one housed right here in Davis – the University of California Integrated Pest Management (UC IPM) program. IPM provides scientifically based information on how to effectively deal with pests whether they are natural or exotic or in urban, agricultural, wildland or natural areas.

Image result for uc ipm

Dr. Jim Farrar, director of UC IPM, recently visited WCAHS and gave a seminar talk on “IPM and Agricultural Worker Safety.” Pesticides are extensively used in farming. In 2014 alone, California registered 2.5 million pesticide applications. Agricultural workers are especially vulnerable to getting exposed to pesticides when directly handling them, such as during mixing or spraying, and when walking through fields and encountering pesticide drift in the air and residue on plants.

UC IPM provides both online and instructor led courses on the newest advances in pest management as well as basic safety skills with pesticides. Farrar stressed that continuing pesticide safety education is key to protecting agricultural workers and their families from harm. For example, workers can learn how to correctly use personal protective equipment when applying pesticides to avoid exposure and why it is important to wash work clothes separately from household clothes.

IPM also provides online information on how to deal with common pests found in the home, on our pets and even on us! For example, IPM has advice on managing ants, rats, lice and fleas. Farrar emphasized that while it is often difficult to eliminate pests 100%, they can be actively managed and controlled with the PAMS approach:

             Prevent pests from infesting.

             Avoid conditions that are conducive to pest damage.

             Monitor for pests and properly identify them.

             Suppress pests with appropriate tactics.

The PAMS approach works because it takes the long-term view of controlling pests. You can find detailed tips on how to manage all types of pests at the UC-IPM website.

Farm Workers Help Design 4 New Heat Illness Prevention Videos


The California Heat Illness Prevention Study (CHIPS) is proud to present 4 new Spanish-language educational videos on:

  1.            Heat and Humidity Index
  2.            Importance of Water, Shade, and Rest
  3.            Symptoms of Heat Illness
  4.            What to Do In Case of an Emergency

The videos are each 2 to 3 minutes long and based on feedback from farm worker focus groups that said they would prefer watching short, informative videos on heat illness rather than receive written pamphlets.

The videos feature real farm workers and CHIPS staff acting out symptoms of heat illness, such as dizziness and fainting, while working in a field. The videos explain the first signs of heat illness and what to do, as well as the importance of drinking water instead of soda, energy drinks, coffee, and beer. Many workers are unaware that consuming these drinks to ‘cool down’ is actually counterproductive because they have high sugar levels and some drinks contain chemicals that give a false sense of energy (caffeine rush). The videos also explain what to do in an emergency.

At the end of each video, 3 short review questions are presented so viewers can review the information and supervisors can discuss the video with their workers.

You can access the videos at

Adjusting to Work in the Heat: Why Acclimatization Matters

UntitledThe joys of summer are here, but with them come the hazards of working in the heat. Acclimatization to heat is an important part of keeping safe as temperatures rise. This natural adaptation to the heat takes time, and from a management perspective, it may require careful planning.

Make acclimatization part of your plan

A good heat illness prevention plan takes into account the need for more breaks, a cool place to rest, the availability of fluids, and the careful allotment of time for a worker to become fully adjusted or acclimatized to the heat. It will need to be flexible based on the intensity of the heat, the level of humidity, the workers’ experience on the job, and the workers’ physical fitness.

Time to adapt

  • New workers on an 8-hour shift should spend only about an hour and a half in the heat on their first day. Their exposure time should increase slowly—no more than a 20% increase per day. Acclimatization depends on each person. It could take 10 days for some and up to 14 days for others.New Worker Acclimazation copy (1)
  • Experienced workers on an 8-hour shift should take about 4 days to acclimatize to the heat. They can spend up to 4 hours in the heat on the first hot day. The second day they can likely manage 5 hours in the heat and about 6.5 hours on the third day. By the fourth day, most healthy workers should be able to tolerate 8 hours in the heat assuming they are well hydrated and have appropriate rest breaks throughout their shift. However, a worker should always listen to how his/her body feels and take necessary precautions of hydration, rest, and shade.Experienced Worker Acclimazation copy (1)


Slide1Fluids are necessary for acclimatization. In fact, failure to replace the water lost in sweat will slow or even prevent the development of the physiologic adaptations to heat. Workers need to drink small amounts of water throughout the day so that they never become thirsty. For moderately intense work in moderate heat, this equates to approximately 1 cup every 15 to 20 minutes. Supervisors should encourage and remind workers to take water breaks. In some cases, when workers are experiencing heavy sweating, drinks containing electrolytes might be warranted.


In the heat, workers need more rest than they would in cooler environments. Provide a cooler place out of the direct sunlight where they can take their scheduled breaks. A shaded or air-conditioned rest area would be best. Air conditioning will not affect acclimatization. Remind and encourage workers that they need to take advantage of these rest breaks.

How does the body adapt?

When workers are initially exposed to hot work environments, they may readily show signs of distress and discomfort. Their core temperatures and heart rates increase. They may experience headaches, nausea, and other symptoms of heat-related illness. The brain’s thermoregulator detects the increases in skin, muscle, and organ temperature and ignites the body’s cooling mechanisms—primarily sweating and vasodilation of the skin’s blood vessels. As the body is exposed to the heat and is given proper recovery time, it begins to adapt. Many physiologic changes occur including an increase in total sweat capacity, sweating beginning at a lower skin temperature and conservation of body salt.

How should workers maintain these benefits?

A few days out of the heat won’t ruin a worker’s acclimatization, but absence from work in the heat for a week or more can result in a significant loss of those helpful adaptations. Upon return, the worker may combat acute dehydration, illness, or fatigue so supervisors need to make adjustments so the worker has time to re-acclimatize. This can take 2 to 3 days when returning to a hot job.

Planning for the heat requires extra care and effort. But a good heat illness prevention plan that allows workers to properly acclimatize will reduce the risk of heat-related illness and death. For more information, visit the NIOSH Topic Page on Heat Stress or the California Heat Illness Prevention Study (CHIPS), which is led by WCAHS investigators. You can read about a day in the life of the CHIPS workers studying heat illness in the agricultural fields.

This blog was first published by NIOSH on 14 July 2014 and adapted here for the WCAHS site.

How healthy is your California neighborhood?

You can easily find out using CalEnviroScreen, an online environmental health screening tool that scores each of the state’s 8000 census tracks for pollution burden and population characteristics.

Sacramento Business Portraits

Gina Solomon, Deputy Secretary for Science and Health, Cal EPA

Gina Solomon, Deputy Secretary for Science and Health at the California EPA, was a recent WCAHS seminar speaker and  explained that each California census tract has been scored for pollution burden and population indicators of environmental health. Pollution indicators include ozone, particulate matter, diesel, drinking water, pesticides, toxic releases, traffic, cleanups, and groundwater. Population characteristics include age, asthma, low birth weight, low education, linguistic isolation, poverty, and unemployment.

To see how your census track is doing,  click on the pollution burden or population characteristic map, find the particular census track you are interested in, and then click on an individual pollution indicator or population characteristic tab. Each census track is color coded. Darker colors indicate a greater score and relatively higher pollution burden / population vulnerability than areas with lighter colors and lower scores. For example, the pesticide burden for the City of Monterey is much less (light color) than the area surrounding the City of Salinas (dark color), which is heavily farmed and famous for fruits and vegetables.


CalEnviroScreen was created to help implement a state law (SB 535) requiring 25% of  proceeds from the state’s cap-and-trade auctions be invested in projects that benefit disadvantaged communities, including 10% for projects located within these areas. Thus, CalEnviroScreen allows the state to identify California communities with the greatest cumulative exposure to pollution and send state resources to those who need it most.

Lucky for us, CalEnviroScreen is also a great resource for public health researchers interested in a specific problem or location or how multiple environmental stressors affect a community. Dr. Solomon pointed out that many of California’s most disadvantaged communities are in rural, agricultural areas, and CalEnviroScreen can provide WCAHS researchers with a wealth of information.

WCAHS Celebrates California Ag Day 2016

How long does it take to adapt to high temperatures? That was one question on the trivia wheel that WCAHS brought to California Ag Day 2016 at the State Capitol on March 16th. The answer, by the way, is 2 – 14 days for the average person to acclimate to high heat.

2A. Leslie at CA Ag Day

Leslie Olivares with the heat illness trivia wheel.

California Ag Day is annual event that celebrates the abundance of California agriculture and its work force – the farmers, ranchers, laborers – and all that agriculture provides to our communities. Over forty exhibitors involved with all facets of state agriculture, including WCAHS Education and Outreach Specialist Teresa Andrews and Junior Specialist Leslie Olivares, step up tables on the west steps of the Capitol for the public to visit.

The popular WCAHS prize wheel focused on heat illness prevention, which is an especially relevant concern for farm workers, or anyone, spending long periods of time working outside during heat events in California. Children as well as adults were eager to spin the wheel to test their knowledge and win a prize.  The relaxed, family friendly event was a great way to promote our educational work and future training on heat illness.

WCAHS thanks California AgrAbility not only for the incredible work that they do for farm worker health, but also for graciously sharing their table with us. We were pleased to be part of California Ag Day and will attend similar outreach events in the coming months. For more information on these events, contact WCAHS at or (530) 752-5253.

Check out this California Department of Food and Agriculture YouTube video to learn more about the day.