The UA Vegetable IPM Team has conducted annual surveys though interactive workshops since 2005 that document insect pest activity and insecticide usage in cantaloupes, mixed melons and watermelons. Overall, the information provided by PCAs and growers during these workshops can be very useful to the melon industry for a number of reasons. First, the data is be extremely helpful in supporting the industries efforts in addressing state and federal regulatory issues by providing "real world" information on insect pest status and insecticides usage that otherwise would not be available. This type of information is invaluable for supporting product re-registrations, as well as demonstrating the importance of a particular pest or insecticides necessary for supporting Sec 18 and SLN requests. Secondly, from an academic perspective, the results of these surveys often provide us with a historic record of insect occurrences that allows us to identify trends in pest activity and insecticide use, and can be useful for prioritizing our research and extension activities. Finally, for PCAs, it can translate their efforts into economic terms for their clientele and confirms their value to the melon industry by showing the importance of key insect pests and their cost-effective management under desert growing conditions. For example, results from these surveys over the past 6 years show that: 1) costs associated with spray applications and management fees have increased steadily ; 2) two-spotted spider mites are clearly a major pest of desert watermelons, but seldom attain pest status or require control in cantaloupes; and 3) the older, broadly toxic insecticides are slowly being replaced with the newer, softer reduced-risk chemistries. The information generated from the surveys is not surprising to Grower's and PCAs as they already know this. However, these surveys document important pest information that can be useful to those less involved with the day-to-day activities of IPM in desert melons. To view a complete summary of the Lettuce Insect Losses and Insecticide Usage surveys in Arizona Spring Melons from 2005-2010, go to this link.

This study was conducted at the Yuma Valley Agricultural Center. The soil was a silty clay loam (7-56-37 sand-silt-clay, pH 7.2, O.M. 0.7%). Spinach ‘Revere’ was seeded, then sprinkler-irrigated to germinate seed Jan 18, 2024 on beds with 84 in. between bed centers and containing 30 lines of seed per bed.  All irrigation water was supplied by sprinkler irrigation.  Treatments were replicated four times in a randomized complete block design.  Replicate plots consisted of 15 ft lengths of bed separated by 3 ft lengths of nontreated bed.  Treatments were applied with a CO₂backpack sprayer that delivered 50 gal/acre at 40 psi to flat-fan nozzles. 
 

Month	Max	Min	Average	Rainfall
January	68	42	54	1.14 in
February	73	47	59	0.50 in
March	77	50	63	0.31 in

 
Downy mildew (caused by Peronospora farinosa f. sp. spinaciae) was first observed in plots on Feb 19  and final reading was taken on February 26, 2024. Spray date for each treatments are listed in excel file with the results.   Disease severity was recorded by determining the percentage of infected leaves present within three 1-ft² areas within each of the four replicate plots per treatment.  The number of spinach leaves in a 1-ft² area of bed was approximately 144. 

The data (found in the accompanying Excel file) illustrate the degree of disease reduction obtained by applications of the various tested fungicides. Products that  provided effective control against the disease include Orondis ultra, Thrive 4 M, Fungout, Cevya, Eject and Zampro. No phytotoxicity was observed in any of the treatments in this trial.

For those of you interested in the latest developments in Vegetable IPM and/or in need of CEU’s, Yuma County Cooperative Extension has created online workshops that offer CEU and CCA credits for both AZ and CA. Current offerings are the recorded workshops from 2021 Southwest Ag Summit. There’s an ag mechanization session entitled “Advances in Weed Control Technologies”, and several others that readers of this newsletter may be particularly interested in including: “Integrated Pest Management Regulatory Update” “Pesticide-Related Updates: The Latest Presented by the Greatest” “Influence of Irrigation on Insect, Weed, and Disease Management” “Advances in Weed Control Technologies” “Integrated Pest Management in Vegetables”. Please recognize Yuma County Cooperative Extension Agricultural Agent Robert Masson who spearheaded this effort. Click on the image, or here to access Veg IPM workshops online.

Weeds that are outside of fields can still be harmful to crop production. This does not include ditch banks or fallow fields. Non-crop weed control includes weeds around buildings, roadways, equipment yards, fence lines etc. It is different than fallow ground or ditch banks weed control and includes places where crops are not grown. Weeds in non-crop areas can be a source of weed seeds that blow or are carried into places where crops are grown. They can also be a refuge for insects,  diseases and rodents. The reason that these herbicides are registered for non-crop areas is that they are broad spectrum and persistent. Some are registered for use in fields but at much lower rates than for non-crop areas. For instance, Diuron can be used on alfalfa at 1 to 1.5 qts/ac. but is used for non-crop areas at 12 qts/ac.

Herbicide	Weeds Controlled	Activity	Soil Residual	Comments
Bromacil	Broadleaves and grasses	Preemergence	1 to 2 years	The nuclear option Should be incorporated with water. Keep away from roots of desirable vegetation.
Hexazinone	Broadleaves and grasses	Preemergence and Postemergence	1 to 2 years	Keep away from roots of desirable vegetation. Incorporate with water.
Diuron	Broadleaves and grasses	Preemergence and Postemergence	2 years	Incorporate with water but do not leach into roots of desirable vegetation
Prometon	Broadleaves and grasses	Preemergence and Postemergence	1 to 2 years	Must be incorporated with water
Tebuthiuron	Broadleaves and grass. Good on hardwood trees	Preemergence and postemergence	2 years	Incorporate with water. Contact with even on feeder root of desirable vegetation can be lethal
Imazapyr	Broadleaves and grasses	Preemergence and post emergence	1 year	Primarily a postemergence herbicide but is readily absorbed by rootsif incorporated with water
sulfometuron	Broadleaves and grasses	Preemergence and post emergence	1 year	Must incorporate with water
Aminopyralid	Broadleaves	Preemergence	1 year	broadleaves only. Shorter soil residual for weeds but crops can not be planted for 1-2 years

 Area wide Insect Trapping Network   VegIPM Update, Vol. 14, No. 21, Oct 18, 2023           
 
Results of pheromone and sticky trap catches can be viewed here.
 
Corn earworm:            
CEW moth increased in Tacna/Roll/Dome last week, and areawide about average for mid-October.
 
Beet armyworm:          
Trap counts highest in Tacna, Wellton and Dome, but below average for October.
 
Cabbage looper:         
Cabbage looper numbers increased in Tacna/Roll/Wellton but still below average.
 
Diamondback moth:    
DBM moths are beginning to appear in traps in Yuma Valley, trending below average for early October.
 
Whitefly:                      
Adult movement increased in the past 2 weeks and above average for mid-October.
 
Thrips:                         
Thrips adult activity down over the past week, and trending below average in October.
 
Aphids:                        
Winged adults continue to be captured for the season, consistent with heavy winds from W-NW. Can expect aphid flights to increase in the coming weeks.
 
Leafminers:                  
Adult activity increased significantly in Tacna associated with maturing melons. Trending above average for mid-October.