Hope you are all enjoying the summer so far and keeping busy. Although, we’re about 2 months away from the Fall produce season, it’s never too early to begin thinking of IPM strategies you will be using to battle key insects next season. This includes keeping track of their typical activity during June, July, and August. Below is a short discussion detailing individual pests. 
 
Aphids:    The major aphid species that are important in produce crops each spring include green peach aphid, foxglove aphid and lettuce aphid.  These species are considered cool season pests and are biologically most active during the winter and spring when temperature average around (55-65 F). We do not find them on summer crops as the high temperatures prohibit their activity. They essentially become extinct each summer only to reappear in the fall to infest crops in Oct-Dec migrating into the desert via N-NW winds that occur after the monsoons.
 
Diamondback Moth (DBM):  Another key pest that disappears each summer but for a different reason than for aphids. The host range of DBM is limited to only brassica crop and plants. Although brassica weeds are common during the winter, they occur during the summer due to high temperatures and dry conditions. Thus, like aphids, DBM populations from the previous spring season become “extinct” during the summer when brassica crops and weeds are absent. They reappear each fall migrating in on high winds associated with tropical storms from Mexico, or arrive into the region on infested brassica transplants from California.
 
Whiteflies:       A resident pest that occurs year-round in the desert. As a warm season pest, whiteflies are most abundant on fall produce crops, and seldom a problem during the winter and spring. Peak abundance occurs during the summer months on cotton, and again in September and October on fall brassica, leafy vegetables and fall melons.  Thus, it is important to control whiteflies in cotton prior to defoliation to prevent large migrations onto fall produce crops. In addition, whiteflies can be found on several weeds such as purslane, goosefoot, ground cherry, and sunflowers. Sanitation in and around fields being prepped for fall plantings is important. Preventatively, growers should consider applying soil, system insecticides such as imidacloprid or Verimark to Fall produce crops.

Beet Armyworm (BAW):  A warm-season pest that occurs year-round in the desert. They tend to reach peak abundance twice a year. Generally, the most important peak is in September and October when weather is ideal for their development, flight activity and oviposition. A second peak occurs in late spring. Activity is generally light during the summer, occurring primarily in alfalfa crops. Although BAW is known to migrate in from the south via monsoon and tropical storms, resident populations annually occur in alfalfa during the summer. Thus, to minimize BAW in fall produce crops, thorough management of BAW can potentially minimize their movement onto Fall produce crops.  Weeds are also a source of BAW (purslane, goosefoot, sunflower and Russian thistle) so sanitation in and around fields is important.
 
Western Flower Thrips (WFT):  Also a resident pest that can be found in the desert year round. WFT is most abundant on lettuce in the late spring, but peaks in abundance on alfalfa, melons and cotton is May and June. During the late summer numbers drop dramatically where thrips can be found on melons and alfalfa and weeds like goosefoot and purslane. WFT slowly move into lettuce again in early fall and are least abundant during the winter.  Sanitation of weeds during the summer can help reduce thrips abundance moving into the fall crops and weeds.
 
For more information see:   Keeping Track of Major Produce Pests During the Summer

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/

Bacterial leaf spot is caused by the bacterium, Pseudomonas syringae pv. Aptata. Hosts of the pathogen include Table beet, Sugar beet, Spinach, Swiss chard, Snap bean, Dry bean, Cantaloupe, Pumpkin, Squash, Lettuce, and Pepper.
 
Significance
Bacterial leaf spot is most commonly found affecting table beet at early stages of growth. This may be because younger plants are more susceptible. It may also be related to the prevalence of cool, wet conditions at the beginning of the cropping season. These conditions are most conducive to infection and disease development. The disease may affect green leaf area in developing seedlings and in severe cases can lead to plant death. Diseased leaves will lead to weakened seedlings which may affect transplant success. Bacterial leaf spot does not directly affect root quality.

Figure 1. Bacterial leaf spot caused by Pseudomonas syringae pv. aptata of
table beet: (left) Small focus of the disease, and (right) 2-6 true leaf stage of
plants affected by the epidemic.

Symptoms
Bacterial leaf spot symptoms are irregular in shape and black to brown in color. The spots may occur across the leaf surface but have a tendency to occur on the leaf edges. Lesions are water-soaked not often accompanied by chlorosis (yellowing). Lesions may initially be small (up to ¼ inch in diameter) but if conditions are conducive may rapidly expand and coalesce but do not cross major veins. The leaf is usually puckered and deformed around the lesions, especially if they occur on the margins (Fig. 2). When the disease is severe, the affected the tissue may also tear giving the appearance of abiotic damage such as hail.

Figure 2. Symptoms of bacterial leaf spot on table beet (cv. Merlin). Note the
black color of the lesions and puckering and deformation of the leaves around
the symptoms.

Bacterial leaf spot symptoms may be confused with other fungal foliar diseases (e.g. Cercospora and Phoma leaf spots; see complementary fact sheets for these diseases) and insect damage (e.g. thrips). Bacterial leaf spot lesions do not have black pin-head, fungal structures across the lesions as found in Cercospora leaf spot. Phoma leaf spot lesions also have small, black structures within the lesions but found in rings and usually accompanied by an ooze of spores.
Disease Cycle
Figure 3. Schematic diagram of the potential sources of Pseudomonas syringae pv. aptata inoculum which may contribute to Bacterial leaf spot epidemics in table beet.
P. syringae pv. aptata may be introduced to the table beet crop through several ways (Fig. 3). P. syringae pv. aptata is seedborne and infested seed is a common means of pathogen introduction into table beet fields. The pathogen can also be present in the infested crop residues from the previous season as well as the alternative hosts. Alternative crop hosts include typical Chenopods (e.g. spinach, sugar beet, and Swiss chard) but also other non-related species including beans, cucurbits, and lettuce. Cool temperatures between 45-60°F and wet conditions typical of those that occur in early spring in upstate New York are conducive for pathogen infection and disease development. These conditions are similar to those that predispose table beet also to Phoma leaf spot. The pathogen can spread within the field through infested seed and irrigation water.
Disease Management
One of the most critical factors to achieve management of bacterial leaf spot is the use of certified seeds (Fig. 4). Other factors that will also contribute to reducing the initial inoculum and hence risk of disease include: (i) tillage to bury plant residues to promote breakdown, (ii) rotation between host crop species of at least three years; and (iii) drip or furrow irrigation to avoid dispersal of the pathogen through water splash. Currently, little is known of differences in cultivar susceptibility to bacterial leaf spot. Anectodal reports have described severe epidemics in cvs. Merlin, Boro, and Pablo.

Figure 4. Complementary practices towards the management of Bacterial leaf spot of table beet.
In-season control. If bacterial leaf spot is severe, applications of copper-based products should be considered to prevent disease spread. There are a range of conventional and OMRI-listed copper-based products available, including: Cueva (copper octanoate; FRAC M1), Badge X2 (copper oxychloride + copper hydroxide; FRAC M1), and Kocide 3000-O (copper hydroxide; FRAC M1). Remember to check the label for rates, re-entry intervals, and pre-harvest intervals applicable to your state and crop. Avoid applying copper-based products on transplants before hardening off, and in high temperatures due to the risk of phytotoxicity.
 
Source: 
https://www.vegetables.cornell.edu/pest-management/disease-factsheets/bacterial-leaf-spot-of-table-beet/

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.

Results of pheromone and sticky trap catches can be viewed here.
 
Corn earworm:            
CEW moth counts decreased considerably y in the past 2 weeks and about average for late summer
 
Beet armyworm:         
Trap counts stay active in some locations (Yuma Dome Valley and Wellton) particularly near alfalfa
 
Cabbage looper:         
Cabbage looper numbers remain low consistent previous years.
 
Diamondback moth:      
DBM moths were not caught in any trap since June; average for this time of the year.
 
Whitefly:                      
Adult movement decreased in past 2 weeks consistent with previous years
 
Thrips:                         
Thrips adults decreasing in most locations, and trending comparable to previous years.
 
Aphids:                       
Aphid movement is absent and consistent with what we typically see during the summer.
 
Leafminers:                  
Adult activity has highest in Wellton and Dome Valley, and slightly above average for early August