Jun 28, 20232023 Insecticide Usage on Conventional and Organic Lettuce
To contact John Palumbo go to: jpalumbo@ag.Arizona.edu
These large fluctuations have been largely due to changes in trade flows with Russia because of the tensions in the region, sanctions imposed on Russia, inflation, and other pandemic-related complications with transportation logistics. Collectively, expensive fertilizer prices have been a challenge globally and certainly in our crop production systems of the desert Southwest.
Recently, several retail fertilizers have varied significantly in the market trends. For example, in May 2023 about half of the major retail fertilizers are higher compared to April prices and the other half has lower prices than last month (Quinn, 2023).
Urea (46-0-0) has gone up 6% in retail markets since last month with an average price of $664/ton. A few weeks ago, urea was below $600/ton for the first time since late 2021. Similarly, diammonium phosphate (18-46-0), monoammonium phosphate (11-52-0), and urea ammonium nitrate (32-0-0) had an average the past month of $517/ton.
In contrast, anhydrous ammonia (82-0-0) has had an average price recently of $910/ton, which is down about 9% in price from April 2023. Several other major fertilizers have been lower in price the past month. Muriate of potash (KCl, 0-0-60) had an average price in the past month of $627/ton, ammonium polyphosphate (10-34-0) average price has been $739/ton, and urea ammonium nitrate (UAN-32, 32-0-0) average price has been $423/ton this month.
Note that several of the major fertilizer materials come in different forms. For example, urea ammonium nitrate (UAN) is 28% N in some materials and 32% N in another common form. Also, monoammonium phosphate (MAP) can have N concentrations of 10-12% and P2O5 concentrations of 48-61% with 11-52-0 being probably the most common form in the market.
Considering the overall trends in the past few years, international fertilizer prices have been generally decreasing since the summer of 2022. Today, international fertilizer prices are back in a range close to early 2021. International fertilizer prices are not expected to drop below pre-pandemic levels, primarily due to global inflation that generates an increase in production and transportation costs (Figure 1).
Several expert sources in the fertilizer industry are projecting a drop in international fertilizer prices in the coming months by approximately 50% of the prices experienced last year. Accordingly, many fertilizer importers are waiting to ship to markets and farmers are often waiting and watching for the projected drop in fertilizer prices to materialize before purchasing (Schnitkey et al., 2023).
Despite the high degree of volatility in international fertilizer markets and the limited availability of fertilizers in some crop production sectors that have recently been experienced, it is expected that the downward trends will continue.
Looking ahead, many experts in the international fertilizer industry are recommending for producers to not wait until too late to purchase fertilizers for upcoming crops, utilize economies of scale when purchasing fertilizers materials as much as possible, and of course watch the trends in fertilizer markets. International logistics in the fertilizer industry, including shipping, transfer, and distribution of fertilizer cargo is proving to be very important in realizing a more stable fertilizer market for the future.
Schnitkey, G., N. Paulson, C. Zulauf and J. Baltz. 2023. Fertilizer Prices and Company Profits Going into Spring 2023. farmdoc daily (13):36, Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, 28 February 2023.
Quinn, R. 2023. DTN Retail Fertilizer Trends: Fertilizer prices moving in two directions. DTN Newsletter, 17 May 2023. https://www.dtnpf.com/agriculture/web/ag/crops/article/2023/05/17/fertilizers-moving-two-directions
As we hear towards harvesting season for melons, we might be seeing some bacterial fruit blotch inf the fruits. Though I hope we do not see them, I wanted you to be prepared for your own diagnosis in case you do. Bacterial fruit blotch (BFB) of melon is caused by the bacterium Acidovorax avenae subsp. Citrulli. The bacteria produces large olive green to brown water-soaked lesions on fruit, making them unmarketable.
Symptoms of BFB on seedlings begin with water-soaked areas on the lower surface of the cotyledons and inconspicuous lesions on leaves. BFB lesions will become necrotic often with yellow halos. Lesions are frequently delimited by veins. Infected seedlings collapse and die.
Greenhouse conditions are usually favorable for dispersal and establishment of pathogen. Thus, good greenhouse practices and sanitation is extremely important. Clean transplant trays must be used (disinfect trays if they will be reused) and new soil. Destroy any volunteer seedlings and keep the area in and around the greenhouse weed free. Avoid overhead watering if at all possible, or water in the middle of the day so that the plants dry thoroughly before evening. The bacterium can spread on mist and aerosols. Relative humidity should be kept low through proper watering and good air circulation in the greenhouse. Separate different seedlots, to reduce lot-to-lot spread. Monitor these isolated seedlings daily and destroy trays where symptoms develop. The remaining trays should be sprayed with a labeled bactericide and the applications continued until the plants are transplanted to the field.
The pathogen can be seedborne, so growers should only use seed that has been tested for the presence of the pathogen by a reputable testing facility. Management of BFB includes a combination of preventing the introduction of the pathogen, sanitation to eliminate any inoculum present, and the use of bactericides if the disease appears. There are no commercially available watermelon cultivars that are resistant to bacterial fruit blotch, but there is some variation in susceptibility among cultivars.
Fig. 1. Finger weeders removing a large, in-row Palmer Amaranth plant in cotton – slow motion video. (Video credit: Kyle R. Russel, Texas A&M University. Cultivator design and setup credit: Carl Pepper, Lubbock, TX). Click here or on the image to see the video.
Surveying the Yuma area, we have observed a lot of Hairy Fleabane (Conyza bonariensis) and received calls from PCA's regarding this weed and its control.
We have observed that the application of Glyphosate is not showing good efficacy in controlling this species in parts of Yuma and Phoenix area.
Resistance to glyphosate has been reported in some grain growing areas of Queensland and northern New South Wales and other cropping regions across Australia (1) as well as Spain (2).
Other cases of resistance to other herbicides such as paraquat, and 2,4-D have been confirmed (3).
In the International Herbicide Resistance Weed Database it is reported that in Switzerland that both Conyza canadiensis (Horseweed) and Conyza bonariensis (Hairy Fleabane) presented resistance to a HRAC Group 9 herbicide last year. We found resistance reported in California only and not in Arizona (4).
Some of our PCA amigos and field technicians have reported having problems finding a good treatment for fleabane due to possible glyphosate resistance. We included Glufosinate and Embed Extra in a trial last year. The images below show good results of an application of Rely at a high rate (82floz) with two applications at a 2-week interval. The second picture shows the efficacy of Embed Extra (2 pt.) following the same application schedule. Weeds were ~2-3” at the time of application. Some growers have reported good results with glufosinate in Waddell AZ. Sharpen has also been used by Yuma citrus growers.
A study showed that plants grown at 90% relative humidity presented more translocation of glufosinate than those grown at 35%. Relative humidity had greater effect than temperature on glufosinate toxicity to Palmer amaranth, redroot pigweed, and common waterhemp (5). In a trial conducted by Barry Tickes from UA nutsedge control was better in an August application with a ~40% RH than a June application with ~20% RH.
As always please check labels and registration before using these treatments.
Figure 1. Hairy fleabane control with Glufosinate
Figure 2. Hairy Fleabane control with Embed Extra
5. Coetzer, E., Al-Khatib, K., & Loughin, T. (2001). Glufosinate efficacy, absorption, and translocation in amaranth as affected by relative humidity and temperature. Weed Science, 49(1), 8-13. doi:10.1614/0043-1745(2001)049[0008:GEAATI]2.0.CO;2