Spring melon harvest is well underway and will coming to an end in a couple of weeks.  Accordingly, now is a good time to begin thinking about whitefly management in fall produce and melons crops.  The first line of defense in avoiding whitefly issues in fall plantings is effectively controlling whiteflies on cotton this summer.  But before considering whitefly management in cotton, it is important that whitefly populations be prevented from building up to large numbers in the spring melons that recently finished or are nearing completion of harvest. Although whitefly abundance has been about average this spring, we anticipate that they will rapidly increase over the next 2 weeks with the forecasted high temperatures and area-wide melon harvests. Growers and PCAs should not hesitate to knock these populations down on pre-harvest melons. Under current weather conditions (high temperatures) immature populations can rapidly build-up and cause honeydew/sooty cold contamination on fruit.  Furthermore, the longer a harvested melon field remains untouched, the more whiteflies that can potentially be produced.  Once harvest is complete, proper sanitation in spring melons is critical for preventing unnecessary whitefly migration into cotton and alfalfa. It is highly recommended that melon growers quickly destroy plant residue as soon as possible following harvest.  A delay in disking under melon fields following harvest can provide a large source of adult whiteflies that will readily disperse into cotton and alfalfa, especially if they don't need to fly very far.  These fields also potentially extend the host-acquisition period for CYSDV.  A quick survey last week showed that overall CYSDV incidence is light (1-2% of fields infected), but almost all fields had some virus on field edges.  Once melons have been disked and flat-watered, it is common for volunteer melons to germinate and emerge during July. The destruction of volunteer melons between spring and fall crops can reduce the source of whiteflies and virus inoculum available.  This can be done by disking or applying a contact, burn-down herbicide to fields. Volunteer melons should be destroyed as soon as practical.   Recent research has indicated that fall melons grown near spring melons with volunteers (<2 miles) are at a high risk of CYSDV infection.  Ideally, it is in the Ag communities best interest to use sound cultural management practices, such as sanitation, to eliminate and avoid unnecessary sources of whiteflies before the fall produce and melon seasons begin.  For more information on cultural management practices for whiteflies see:  Cultural Practices for Whitefly Management in Desert Melons.

Every day, each of us generally consumes about 100 gallons of water for our basic needs of drinking, bathing, cooking, toiletries, etc.  (USGS, 2019; Kobir, 2024; and Philadelphia City Government, 2024).  The United States Geological Survey (USGS) estimates that the average American needs 80-100 gallons per day for basic use and consumption (indoor use).  The Arizona Department of Water Resources (ADWR) estimates that Arizonans consume an average of 146 gallons of water per day (ADWR, 2024).
 
As discussed in a recent article in this newsletter (Silvertooth, 2024) the water required to produce the food supporting an average Arizonan can range from 800 to 1,500 gallons per day.  Thus, we can use an estimate of 1,000 gallons consumed per day to support our individual food requirements (Anyabwile and Walker, 2019; Wheeler, 2022; Food Print, 2024; Michel, 2023; Smith, 2012).  
 
If this estimate of “virtual water” use is expanded to include clothing, appliances, vehicles, and other items in our common daily use the average water footprint for Americans easily comes up to 2,000 gallons of water per day (ASPE, 2022).
 
Looking at this more closely, we can see quite a wide range of water requirements to produce some common food items (Figure 1).  It is interesting to note the increasing water requirements associated with meat products and that beef is commonly found at the top of the list.

Figure 1.  Water requirements to produce some common food
items.  Source:  World resources institute, Anyabwile and Walker, 2019.

Considering daily indoor use and diet, a person can develop estimates on their own personal daily water consumption and water footprint by use of one of the water footprint calculators available on-line (i.e., Water Footprint Calculator).
 
Some good examples of water requirements (footprint) for basic food and daily use products include the following (Wade, 2024):
 

• One cup of coffee is estimated to be around 37 gallons. 
• It takes about 365 gallons of water to make Spaghetti sauce with ground beef, garlic, oregano, onion, and basil according to the USDA. 
• Sixty-five gallons of water are needed to produce a serving of rice and beans.
• The fruit in a fruit medley requires 71 gallons of water.
• It takes a total of almost 3,200 gallons of water to produce a mobile phone that includes numerous water-intensive stages, from mining rare minerals to assembling electronic components.  
• A substantial amount of water is needed to provide the ongoing charging required for electric vehicles.  This includes all the steps from the mining of lithium for batteries to manufacturing vehicle components. 
• Approximately 13,700 to 22,000 gallons of water is required to produce each of our standard vehicles.
• The data centers that support the extensive digital landscape we navigate daily require huge amounts of water for cooling systems and infrastructure maintenance.  For every 200 gigabytes of internet access approximately 40 gallons of water is needed, or about one-fifth of a gallon per gigabyte is required.
• A plastic water bottle requires twice as much water to produce the plastic than the volume of water in the bottle.
• One gallon of gasoline requires up to 2.5 gallons of water to refine it.
• One pair of leather shoes requires more than 2,100 gallons of water to produce.

 
The important point to consider is that we all use more water every day than is commonly realized.  Water is essential to support all life and it takes a lot of water to grow plants and support animals that everyone needs to live and survive.  
 
There is a strong demand for the food products shown in Figure 1 and all other food products as well.  As consumers, we are all the direct beneficiaries of the water used to produce the crops with all the fruits and vegetables that come from them.  Healthy animals require good food, which all comes from plants, i.e., alfalfa.  Everything we consume has a significant water footprint. 
 
We commonly devour our way through tons of good food while being totally oblivious to the reality of what it takes to put it all in the markets and ultimately on our kitchen tables.  It is good for us to recognize the realities of the water requirements that support the production and provision of our food, particularly in these times of water shortages.

 
References:
Anyabwile, A. and S. Walker.  2019.  5 Ways to put food on a water diet.  World Resources Institute.  https://www.wri.org/insights/5-ways-put-food-water-diet
 
Arizona Department of Water Resources.  2019.  Water Your Facts.  Arizona Water Facts.  https://www.arizonawaterfacts.com/water-your-facts
 
Arizona Department of Water Resources (ADWR).  2024.  Conservation.  https://www.azwater.gov/conservation/public-resources
 
ASPE.  2022.  New research shows most Americans are unaware of their daily water consumption.  ASPE Pipeline.  https://aspe.org/pipeline/new-research-shows-most-americans-are-unaware-of-their-daily-water-consumption/#:~:text=Most%20believe%20they%20use%20less%20than%20100%20gallons,indirectly%20%28e.g.%2C%20the%20water%20required%20to%20produce%20food%29.
 
Food Print.  2024.  The Water Footprint of Food.  https://foodprint.org/issues/the-water-footprint-of-food/
 
Kobir.  2024.  How many gallons of fresh water do we use per day.  https://medium.com/rocklinca/how-many-gallons-of-freshwater-do-we-use-per-day-7987edf6b1bb
 
Michel, D.  2023.  Water and Food: How, When, and Why Water Imperils Global Food Security.  Center for Strategic and International Studies.  https://www.csis.org/analysis/water-and-food-how-when-and-why-water-imperils-global-food-security
 
Philadelphia City Government.  2024.  Gallons Used Per Person Per Day.  https://water.phila.gov/pool/files/home-water-use-ig5.pdf
 
Smith, T.  2012.  World Water Day: How much water do you use in a day?  Climate Home News.  https://www.climatechangenews.com/2012/03/22/world-water-day-how-much-water-do-you-use-in-a-day/
 
United States Geological Survey. 2019.  How much water do I use at home each day? https://www.usgs.gov/special-topics/water-science-school/science/water-qa-how-much-water-do-i-use-home-each-day
 
Wade, M.  2024.  Where does our water wind up?  Ag Alert, California Farm Bureau Federation.  7 February 2024.
 
Water Footprint Calculator. 2024.  https://watercalculator.org/water-footprint-of-food-guide/
 
Wheeler, M.  2022.  Did You Know’ Series: How Much Water Are We Actually Using?  Virginia Water Resources Research Center, Virginia Tech University.  https://www.vwrrc.vt.edu/2022/03/31/did-you-know-series-how-much-water-are-we-actually-using/

Late blight of celery is caused by fungi Septoria spp. The disease is named late blight as it is mostly seen at the later in the growing season but don’t be surprised if you see the symptoms in early season when the weather is conducive. With the rain and fog we had this week, it is possible that we get this disease in celery this growing season. Leaf spots are dark, circular to irregular in shape, and 3-10 mm in diameter. Dark colored fruiting bodies (pycnidia) of the fungus which form in the center of leaf spots give the spots a grainy appearance. In case of severe infection, large number of spots are formed and can significantly reduce yield. Sometimes, angular spots are seen as the symptoms are restricted by leaf venation. The stalk or petiole of the plants can also be infected and large number of pycnidia observed in the stalk. Pycnidia is basically huge amounts of asexual spores in dark fruiting bodies and are formed on the older lesions and their development is encouraged by moist weather.

The pathogen is seed borne but will survive in soil in decomposing celery tissue for months. Cool and wet weathers favor the disease. Temperatures below  75 F are conducive to disease formation. High humidity allows abundant production of spores and epidemics are initiated by splashing spores or by movement of spores by contact. Rain, heavy dew or fog, and sprinkler irrigation when temperatures are above 70°F encourage disease development; splashing water disperses spores and aids in spore germination and infection

 Acquiring clean seeds is the best management practice for the disease. Hot water treatments are effective but might interfere the germination percentage. Clean cultivation, not planting new crop next to the infected crop field, crop rotation, and fungicides can be used to manage the disease.  Avoid sprinkle irrigation after symptoms are observed. Copper sprays can be used in organic farming. 

Interested in the latest automated weeding technologies? University of California Cooperative Extension will be hosting the 2024 Automated Technology Field Day where twelve of the newest commercial and academic thinning and weed control technologies will be demonstrated in the field. Featured technologies, some showcased for the first time to a general audience, include a high voltage electric weeder that kills weed seed pre-emergence, laser weeders (two types), “smart” precision spot sprayers (four types), “smart” in-row cultivators (four types), and the UA/UC Davis smart steam applicator for killing weed seed and soilborne pathogens pre-emergence. Company representatives and university personnel will be on hand to discuss their equipment. The event will be held from 9:00 am – 12:00 noon, Thursday, June 27^th in Salinas, CA. For additional information, see the event flyer below.

Boerhavia coulteri is a flowering plant that belongs to the Nyctaginaceae or Four O'clock family known by the common name Coulter's spiderling. Its native to the desert areas of the SW in the US and North of Mexico. It is a summer annual or perennial weed producing an erect or creeping stem up to 0.7-0.8 m in length. Grows in disturbed areas, ditch banks, and roadsides.

The cotyledons are oblong,1.0-2.5 cm.

Plants are slightly pubescent with sticky resin glands toward the bases. The leaves are lance-shaped, somewhat triangular, pointed, sometimes wavy or rippled along the edges, and 5 centimeters in maximum length¹.
We have this weed in our Yuma County AZ and very abundantly in the sandy soils of the Yuma Mesa.
I added a table from a weed control experiment conduced for Boheravia erecta.
 
The Research Paper called :” The effect of herbicide tank mix on the weed species diversity
in sugarcane (Saccharum officinarum)” mentions: “All the herbicide mixes significantly controlled Boheravia with Pendimethalin. Being Pendimethalin plus Atrazine the best treatment as shown in the table below.

1. Retrieved from: https://en.wikipedia.org/wiki/Nyctaginaceae
2. Retrieved from: https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=f6c87c4485da5772f26997828b5d4eaf9e856541

Biological control is one of the key tools for pest management in organic crop production. By maintaining permanent habitats and food sources for the pests’ natural enemies (good bugs) in the vicinity of your farms, you can ensure the continuous availability of the natural enemies. When the growing season starts, the good bugs will be readily available to attack the pests before they become established in the crops. 

Researchers have found that planting a diversity of flowering plants (e.g., sweet alyssum, nasturtium, milkweeds, common cryptantha, hillside vervain, wild petunia, etc.) on a small portion of your farms or the farms’ border can provide adequate food and shelter allowing to maintain abundant and diverse natural enemy species, including syrphid flies, tachinid flies, lacewings, parasitic wasp, etc. that will attack aphids, thrips, lepidopterans, and more. 

As you plan for the next season, please consider planting flowering plants on your farms’ borders or on dedicated patches to conserve natural enemies and enhance your biological control.

Area wide Insect Trapping Network   VegIPM Update, Vol. 15, No. 21, Oct 16, 2024

Results of pheromone and sticky trap catches can be viewed here.

Corn earworm: CEW moth counts increased in most traps; about average for early October.

Beet armyworm: Trap counts increased in most areas last week, and about average for early October.

Cabbage looper: Cabbage looper trap counts still most locations, below average for this time of the season.

Diamondback moth: Adult activity increasing, particularly in the Yuma and Dome Valleys.  Above average for this time of season.

Whitefly: Adult movement increasing Tacna, Dome Valley and Yuma Valley; overall about average for early October.

Thrips: Thrips adult movement picking up in all areas, overall activity above average.

Aphids: Winged aphids beginning to show up the north Yuma and Gila Valleys; about average for early October.