Now that the produce season is essentially finished, it time to move into melons.  Spring melon crops are rapidly growing, and so are insect pest populations. Cabbage loopers and leafminers are becoming evident in some areas, and PCAs should start ramping up their monitoring and sampling. More importantly, whitely populations are quietly becoming abundant on the spring melons of all sizes. Adults can easily be found on recently planted melons located at the Yuma Ag Center, and reports from local PCAs suggest that adult populations are beginning to show up on older plantings. As temperatures increase and crops/weeds mature, avoidance of excessive feeding from whitefly nymphs should be the primary concern on all melon types. Although CYSDV does occur in later spring melons, it is rarely yield limiting. But honeydew and sooty mold contamination on cantaloupes, mixed melons and watermelons can significantly reduce quality and marketability is whiteflies are not adequately controlled.  Our research has shown that to prevent fruit yield and quality losses on spring melons, a foliar insecticide treatment should be applied on threshold; that is, when leaves have greater than 2 adult whiteflies per leaf, when averaged across an entire melon field. At this level of adult abundance, immature populations are just starting to colonize, and timing sprays based on the adult threshold has been shown to significantly reduce the chance of yield / quality losses during spring harvests.  This threshold applies for the use of recommended IGRs (Courier, Knack, Cormoran, and Oberon), foliar applied neonicotinoids (Assail, Venom, Scorpion), neonicotinoid-like compounds (Sivanto prime and Transform), diamides, (Exirel and Minecto Pro) and the new feeding disruptors (PQZ and Sefina).  For more information on whitefly management and available insecticides, go to these documents on IPM and Whitefly Management  and  Whitefly Control Options-Spring 2021.     Also, be aware of honey bees and other pollinators in or around melon fields. If bees are present, be sure to carefully read labels and determine bee safety of a product before making an application in a melon field.  If applications are necessary during bloom, only apply a product that is considered bee safe (e.g., PQZ, Sefina, Sivanto, Assail). We also recommend that insecticides only be applied when honeybees are not actively working in the field (e.g. 10:00 pm – 3: 00 am).

Everything we eat and much of what we are surrounded by in our daily lives have a common base from water and the production of green plants.  Anything made of carbon, even if the immediate source of carbon is a petroleum-based product, has an original derivation that starts with green plants and water. 
 
Green plants perform the miraculous process of photosynthesis that captures light energy from the sun to combine with water (H₂O) taken up from the soil through the root system, carbon dioxide (CO₂) from the air, forming a simple 6-carbon carbohydrate compound (C₆H₁₂O₆), and liberating free oxygen (O₂) into the atmosphere. 
 
Photosynthesis involves a complex system of biochemical reactions, but the fundamental photosynthesis process can be reduced to very simple terms as outlined in Figure 1.

Figure 1.  Basic photosynthesis reaction.  (Source: Collegedunia).

Figure 2 offers a little more detail in the photosynthetic process and there is still more to the story.  But the essentials are outlined in Figures 1 and 2.

Figure 2.  Connections between photosynthesis and plant respiration.

The process of taking CO₂ from the atmosphere and “fixing” the carbon in a larger and more complex form as a basic carbohydrate (simple sugar compound) is referred to as “carbon fixation” and green plants provide most of this primary function in the earth terrestrial, or land-based ecosystems.  
 
Carbon fixation is conducted by organisms containing chlorophyll and green plants do most of this work.  There are also some species of algae and cyanobacteria that can fix carbon from the atmosphere.  But green plants, using energy from the water and water from the soil are the real workers in our world in this regard.
 
Water is essential in this process of fixing carbon through photosynthesis.  In fact, six units of water are required for every unit of carbohydrate that is produced (Figure 1).  
 
Additional water is used by the plant in the transpiration process, which is the movement of water from the soil through the root system, through the conductive tissues of the plant.  This provides for good cellular hydration and biological function.  In the transpiration process water moves out of the plant and escapes into the atmosphere as gas through the stomates, which are small openings in the underside of plant leaves (Figure 3).

Figure 3.  Plant transpiration.  Source: Premium Vector

Through this process of photosynthesis, water and green plants serve as the backbone of all terrestrial life.  These are fundamental facts and critical functions that we manage in crop production systems.  Essentially, every field with a green crop growing is a photosynthetic factory and water is always an essential component.  
 
Consumers directly benefit from 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 and much of that involves supporting plant photosynthesis.
 
The inescapable fact is that we need the plants, and the plants need water to grow and produce.

Botrytis rot is not considered a major problem in lettuce but it can cause significant damage/loss when the field conditions are favorable for the pathogen. Cool wet conditions are favorable for the pathogen. Symptoms include water-soaked, brownish-gray to brownish-orange, soft wet rot that occurs on the oldest leaves in contact with the soil. Old leaves are more susceptible than young leaves and the fungus can move into the healthy parts. Fuzzy gray growth can be observed in the disease area which is characteristic of the pathogen. In worse cases, the entire plant can collapse. Romaine cultivars, transplanted lettuce that are big and have leaves touching the soil are more susceptible. 
The pathogen: Botrytis cinerea 
Botrytis cinerea affects most vegetable and fruit crops, as well as a large number of shrubs, trees, flowers, and weeds. Outdoors Botrytis overwinters in the soil as mycelium on plant debris, and as black, hard, flat or irregular sclerotia in the soil and plant debris, or mixed with seed. The fungus is spread by anything that moves soil or plant debris, or transports sclerotia. The fungus requires free moisture (wet surfaces) for germination, and cool 60 to 77 F, damp weather with little wind for optimal infection, growth, sporulation, and spore release. Botrytis is also active at low temperatures, and can cause problems on vegetables stored for weeks or months at temperatures ranging from 32 to 50. Infection rarely occurs at temperatures above 77 F. Once infection occurs, the fungus grows over a range of 32 to 96 F.
 
Masses of microscopic conidia (asexual spores) are produced on the surface of colonized tissues in tiny grape-like clusters (see picture). They are carried by humid air currents, splashing water, tools, and clothing, to healthy plants where they initiate new infections. Conidia usually do not penetrate living tissue directly, but rather infect through wounds, or by first colonizing dead tissues (old flower petals, dying foliage, etc.) then growing into the living parts of the plant. 
 
 
Disease management: 
1. Buy high-quality seed of recommended varieties. Treat the seed before planting.
2. Practice clean cultivation. Plant in a light, well-drained, well-prepared, fertile seedbed at the time recommended for your area. If feasible, sterilize the seedbed soil before planting, preferably with heat. Steam all soil used for plantbeds at 180 F (81 C) for 30 minutes or 160 F (71 C) for one hour.
3. Avoid heavy soils, heavy seeding, overcrowding, poor air circulation, planting too deep, over-fertilizing (especially with nitrogen), and wet mulches.
4. Focus on healthy plant vigor. Do not over fertilize. 
5. Use drop or furrow irrigation instead of sprinklers. If sprinklers have to be used, irrigate morning or early afternoon giving enough time for foliage to dry. 
6. Apply recommended fungicides when conditions favor disease development. Make sure to rotate fungicide to avoid development of resistance. 

AI is in the news all the time being touted as the most influential human innovation in history. Why? I’m not sure exactly as generally few specifics are given, but recently came across an article that gave me some insight as to what the experts are talking about. The piece focuses on a project by Google DeepMind¹: two AI robots playing soccer (Paul, A., 2024). There’s a couple of things that struck me most about the robots. The first was how human-like their behavior and actions were. They reminded me of a couple of 5-year-olds playing soccer. The second is the manner in which they learned. Unlike traditional programming methods where every action is meticulously coded, these robots were given the objective of scoring a goal and only provided instructions on how to stand up and kick a ball. The rest they taught themselves using deep reinforced learning (AI) methods. The news program 60 Minutes also reported on the AI soccer playing robots (Fig. 1). Check out the article here and the 60 Minutes segment in the video below. I think you’ll be impressed.

Fig. 1. 60 Minutes Segment: Google DeepMind demos AI training robots to play soccer / football. (Credit: 60 Minutes). References

References
Paul, A. (2024). Watch two tiny, AI-powered robots play soccer. Miami, Fla.: Popular Science. Available athttps://www.popsci.com/technology/deepmind-robot-soccer/.
____________________
[1] Reference to a product or company is for specific information only and does not endorse or recommend that product or company to the exclusion of others that may be suitable.

Why is it that the summer months we spray herbicides, and they don’t work for some weed species. 

For example, during the hot time of the day and when desert weeds are stressed for moisture even the highest rate of Glyphosate sometimes is not effective.
Some desert weeds develop physical characteristics and growth habits that equip them to survive hot and dry conditions. We have seen that some species have different response to herbicides in cool areas than our low desert. 

Weeds in the desert have a thicker skin to preserve water. The stomates, which are the pores found in the epidermis of leaves, stems, and other organs, controlling the rate of gas exchange between the internal air spaces of the leaf and the atmosphere are closed¹. Plant transpiration is reduced, and this interferes with the translocation of herbicides in the weeds.

Take as an example Purslane, which has very succulent leaves and stems and can survive incredibly high hot and dry conditions. Then when weather is more favorable it comes out of survival mode to start growth again at the presence of moisture.

Other perennial species have underground structures that help them survive such as Nutsedge and bermudagrass have tubers, and rhizomes.
Lundkvist² stated:” The conclusion is that environmental conditions that promote growth rate of the weed stand will also increase the herbicide effect. The results were based on data from two field experimental series performed at six sites in southern Sweden during 1991–1994”.



 References:
1. https://simple.wikipedia.org/wiki/Stomata
2. A. Lundkvist,
Predicting optimal application time for herbicides from estimated growth rate of weeds,
Agricultural Systems,
Volume 54, Issue 2, 1997,

Integrated pest management (IPM) involves the utilization of a combination of several tactics for the effective management of pests. This concept was developed by entomologists and is currently adopted by pest managers to target many kinds of pests, including insects, weeds, and pathogens. Most IMP tactics fit well in both conventional and organic crop production. It is not uncommon that most pest management techniques that are approved for organic crop production are not very effective as a stand-alone tactic. Therefore, it is essential to use a combination of pest management techniques that will complement each other to control the pests adequately. This is like a many little hammers approach, where each of the management tactics is a little hammer hammering on the pests. When planning your IPM programs targeting pests in organic crop production, it is important to consider planting resistant/tolerant varieties, scouting regularly, implementing economic thresholds (when possible), practicing cultural control, physical/mechanical control, and biological control, and applying biopesticides when necessary. 

• Resistant varieties: Resistant varieties are crucial for effective IPM in organic crop production. When available, the use of resistant varieties should be the first line of defense against pests. Resistant varieties help save on production costs and mitigate environmental impacts associated with insecticides and their applications. 

• Cultural control: Cultural control includes cropping systems (trap cropping and push-pull), planting date (early planting or late planting), crop rotation, and growing of crop varieties with early maturity traits. Implementing trap cropping and/or push-pull systems can cause the diversion of insect pests. Early or late planting, crop rotation, and variety with early maturity traits can favor the avoidance of damaging insect pest pressures. 

• Scouting: Proper and timely scouting helps determine the levels of pest infestations, allowing the pest manager to trigger control action in a timely fashion. Scouting also helps to prevent unnecessary insecticide applications. 

• Economic thresholds: The economic threshold determines the pest or injury level at which control action should be taken. The economic threshold works side by side with scouting. This helps to determine when a management action should be triggered, allowing a reduction of unnecessary insecticide utilization, which will consequently help in delaying or mitigating resistance. 

• Physical/mechanical control: This method includes establishing physical barriers, plowing, and sanitation (elimination of volunteer crops and other potential hosts). Plowing can help to bury soil insect pests deep into the ground, directly kill them, and expose soil insects to adverse weather conditions, birds, and other predators, which will adversely impact these pest populations. 

• Biological control: This method involves using insect pests’ natural enemies, including predators such as spiders, lady beetles, syrphid fly larvae, big-eyed bugs, pirate bugs, lacewing larvae, and parasitoids such as parasitic wasps and flies. 

• Biopesticides: Biopesticides are based on botanical extracts, entomopathogenic fungi, entomopathogenic bacteria, or entomopathogenic viruses that have adverse effects on insect pests. Entrust, Bt, Pyganic, AZA-Neem, M-Pede, Celite, and Venerate are commonly used insecticides for insect pest control in organic crops grown in Arizona. 

The implementation of IPM permits to manage pests economically while preserving the environment and reducing negative impacts on human health. In other words, IPM aims at managing pests in an economically viable, socially acceptable, and environmentally safe manner. It is important to note that all the IPM tactics are not always viable in all situations (IPM is not a one-size-fits-all). Therefore, the management techniques choice for an IPM program should be done on a case-by-case basis. 

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