Understanding Diamondback Moth: Crop Protection and Mating Disruption

Are you a cole crop grower or crop advisor for cole crops? Diamondback moth is one of the largest threats to cole crop yields worldwide. Learn more about this pest and how to effectively manage DBM population with pheromone-based mating disruption.

Introduction to Diamondback Moth

Found in North America during the 1850s, Diamondback moth (Plutella xylostella) is a significant pest of cole crops such as broccoli, cabbage, collards, kohlrabi, and brussels sprouts, as well as cruciferous weeds, including wild mustard and shepherd’s purse. While diamondback moth only feeds on plants in the family Brassicaceae, the insect has an incredibly wide geographic distribution and can be found wherever cole crops are grown. Diamondback moth has also earned a reputation for becoming resistant to many different types of insecticides over the years.

Diamondback Moth Pest Description

Diamondback moth adults are small and slim, with a brown/cream colored stripe along the back, that when wings are constricted, form a pattern that shows one or more diamonds. While adults live for roughly two weeks and are considered weak flyers, they are known to disperse very well in the wind, allowing them to travel to regions where they do not (or cannot) normally overwinter.

The eggs of the diamondback moth can be difficult to find as they are often laid on the underside of leaves and appear as very small, flattened ovals. Once hatched, diamondback moth larvae will move through four instars as they mature. Young larvae will damage the underside of leaves, chewing/rasping the tissue until the upper surface of the leaf remains, appearing transparent (known as “window paning”). As the larvae grow, they will begin to chew small holes through the plant with higher infestations causing severe skeletonization of the leaves and, ultimately, significant crop losses. If infestations are high early enough, they can lead to disruption of head formation in crops such as cabbage, broccoli, and cauliflower.

Under warm conditions, the diamondback moth can move through a complete life cycle within 3 to 4 weeks. In warmer climates, an area may see as many as 12 generations throughout the year - this, coupled with the ability of adult females to produce as many as 300+ eggs over the course of their lifetimes and the ability of the insect to develop resistance to conventional insecticides, means that crops can be under tremendous pest pressure.

Why Suterra mating disruption?

Diamondback moth has become notorious for its ability to overcome conventional insecticide products, necessitating growers to constantly rotate modes of action in fields where the pest has a continuous presence. Mating disruption is a proven technology that gives growers another tool in the fight against diamondback moth. With mating disruption, growers can use the biology of the pest against itself, confusing adult males and rendering them unable to locate females with whom to mate.   One advantage of using a mating disruption mode of action is that there is no concern for diamondback moths to develop resistance to this method of pest control, unlike conventional insecticides. Furthermore, the targeted nature of mating disruption products means that beneficial insects and natural enemies of diamondback moths are not adversely affected.

Suterra’s CheckMate® DBM-F sprayable mating disruption product offers a convenient and flexible method of delivering mating disruption to the field in much the same way a common agrochemical product is delivered. CheckMate®, a microencapsulated sprayable formulation, introduces billions of microscopic dispensers into the field that slowly release the pheromone over time to provide mating disruption activity for approximately 30 days. 

Application of DBM-F Sprayable Formulation

When applying CheckMate^® DBM-F, it is important first to shake the bottle vigorously to properly mix the product, as separation is common in microencapsulated formulations. CheckMate^® DBM-F is compatible with many common agrochemical products, allowing for tank mixes and “free-ride” applications. Stand-alone applications of DBM-F can be made at lower volumes and faster speeds, as coverage of sprayable pheromones is not critical as it is for conventional insecticides because pest contact or ingestion is not required. CheckMate^® should be applied immediately after mixing applied as a tan-mix or stand-alone application. Caution should be taken to plan applications after irrigation events to ensure maximum efficacy. 

Frequently Asked Questions for CheckMate^® DBM-F

• Q: What counts as a significant irrigation event?
  • A: Applications of DBM-F should be coordinated to avoid immediate irrigation events amounting to one-third of an inch in the following 24-hour period. Most operational spray programs allow DBM-F to be tank mixed with other sprays at 30-day intervals to minimize irrigation issues.
    
    
• Q: Is there a minimum acreage needed for application for mating disruption to take effect?
  • A: While all pest management methods result in better overall control when coordinated over larger areas. there is no minimum acreage that is needed to see a positive impact from mating disruption in your field.
    
    
• Q: When is the best time to apply this product?

• • A: It is best to apply this product as early as possible to get ahead of rising populations of diamondback moth. It is common for growers to treat plants before or after transplanting. Because DBM is present throughout the growing season, growers can benefit from continued use of CheckMate® from planting to harvest.

• Q: How do we know mating disruption is having an impact in the field?
  • A: If you are monitoring DBM populations using traps and lures throughout the season, you will see fewer incidents of trap capture following an application of CheckMate® DBM-F as the flowable renders the males unable to find the lures within traps. Evaluation of crop damage throughout the season and at harvest will further support the efficacy of mating disruption.