Supplementary Feeding for Biological Control: A Complete Guide

In a world striving for sustainable agricultural practices, the search for eco-friendly and long-term solutions to pest problems has intensified. Biological control methods are often employed in crops to maintain this sustainable agricultural approach, but how do you maintain these biological control methods once applied?

In certain situations, one effective approach for maintaining a healthy biological population is supplementary feeding, which involves providing nutritional support to beneficial insects and mites that naturally prey upon pests. This article explores the concept of supplementary feeding for biologicals, the pros and cons, types of feeding products available, and provides insights on how to apply them effectively in the crop. 

 

Understanding Supplementary Feeding for Biological Control: What is it?  

Supplementary feeding for biological control involves providing additional food sources to enhance the population and performance of beneficial insects and mites which are used to help control pests like spider mites, whitefly, and thrips. 

 

Advantages when adding Supplementary Food:  

• Provided the beneficials environmental needs are met, supplementary feeding can establish a larger population of beneficials than without, ensuring higher levels of pest protection in your crop. Typical environmental needs include; presence of specialized plant hairs necessary for oviposition (egg laying) and high enough relative humidity for the eggs to hatch out properly. 

• Supplementary feeding helps meet the nutritional requirements for many beneficial insects, thereby increasing their fecundity, rate of development and overall survival, ensuring a larger, more stable population of biocontrol that will persist longer in the crop. This can provide a big advantage, both in terms of providing food to prevent starvation in low prey situations and in ensuring a more diverse food source in high prey situations which supporting higher fecundity. 

• Supplementary food can mitigate challenges including starvation, cannibalism, and intraguild predation. Negative effects such as competition, cannibalism, and intraguild interactions among phytoseiid mites may become pronounced as food availability decreases. 

• Starvation – During periods of low prey source in the crop, biocontrol may die of starvation prior their normal life span. Supplemental feeding can maximize their life span. 

• Cannibalism - When there are too few food resources available on crops, many species of generalist predators engage in cannibalism, negatively influencing population growth.  Supplemental feeding provides an abundance of preferred prey/food sources minimizing incidences of cannibalism. 

• Intraguild Predation – is when different species of biocontrol prey on one another. Providing a supplemental food source can reduce levels of intraguild predation. 

 

Cautions to consider in Supplementary Feeding:  

• Unsuitable Environment - Supplementary feeding strategies work best on crops that provide a proper crop surface and climate for beneficials to reproduce on. Outside of this, supplementary feeding will only minimize starvation, at most slightly extending the life span of the predators at the expense of decrease feeding on pests.  On these types of crops, beneficial insects are typically re-introduced weekly anyways so there is a minimal to potentially negative effect from supplemental feeding. For instance; many ornamental crops and cannabis do not have sufficient plant leaf hairs for predator mites to oviposit on, so any positive influence of increased fecundity from supplementary feeding cannot be realized. 

• Application Cost – Though the cost of supplemental food is typically not prohibitive, labor costs can be, as they usually need to be re-applied weekly or bi-weekly. The return on investment needs to be much higher for crops where additional application labor is used to apply supplementary food. This is not really an issue in situations where Airobugs/Mini-Airbugs are already being used for weekly beneficial mite applications, as supplementary food can be used with these machines as well.

• Allergens – All supplementary feed products come with some degree of allergen risk, especially in the case of pollen but also other feed products to some extent. 

 

Types of Supplementary Feeding Products on the Market:  

 

Nutemia: Carpoglyphus lactis (feeder mite) and Artemia spp. (brine shrimp cyst) 

In most situations, Nutemia is the number one feeding supplement we recommend for predator mite supplemental feeding. 

This supplementary food source is primarily used to raise crop levels of predatory mites such as Limonica (Amblydromalus limonicus), Swirski (Amblyseius swirskii), Spical (Neoseiulus californicus), Anso-Mite (Amblyseius andersoni) and Thripex (Neoseiulus cucumeris). 

With extensive trial work on Nutemia, a few things were noticed in regards to Western Flower Thrips (WFT) control: 

• The presence of Artemia spp. reduces leaf damage caused by thrips and the number of predatory mite eggs killed by thrips.  

• Single predatory mites will eat less thrips when Artemia is present. However, at the same time the predatory mite population is growing faster, when Artemia is in the crop, so there will be more predatory mites present to feed on the WFT population. 

Despite this slight negative effect of supplementary feeding on predation of WFT, biological control improves with this product because the predatory mite population increases, and more predatory mites in the crop means more predatory mites feeding on WFT. 

Nutemia can be combined with predator mites in Airbug blowers for single applications that provide even dispersal and reduced labor cost. Airbugs should always be used for this product to ensure even dispersal. 

Nutari: Carpoglyphus lactis (feeder mite) 

Nutari is used exclusively for the buildup of predatory mite populations. These beneficial mites can complete their entire life cycle, feeding only on this feeder mite. In most situations, Nutemia delivers higher levels of predator mites in the crop than Nutari, due to the extra food source, but both of these products (Nutemia/Nutari) are typically better supplementary food sources than pollen or plain brine shrimp cysts. 

Most mass predatory mite rearing systems use Nutari as the prey source, and research shows that in some situations Nutari can increase predatory mite numbers up to 300-500% when combined with appropriate climate and leaf conditions. Some of the predatory mites that work well with C. lactis include Limonica (Amblydromalus limonicus), Swirski (Amblyseius swirskii), Spical (Neoseiulus californicus), Anso-Mite (Amblyseius andersoni) and Thripex (Neoseiulus cucumeris). 

The last advantage to using the above supplementary food sources (Nutemia/Nutari), in situations where you’re not using sachets, is that it can easily be applied with Airbug systems, in conjunction with our predatory mites, so only one application is needed. 

An Airbug or similar system will also ensure adequate dispersal through the crop as feeder mites can cause minor leaf damage, if applied by hand in small piles. This phytotoxicity usually occurs when this product is placed out by hand and left in clumps on the leaves. You will not see this if you place this product out with an Airbug machine. 

It works in all crops where climatic conditions are suitable and predatory mites can establish (chrysanthemum, roses, cucumber, eggplants, peppers, strawberries etc.). In certain crops the residue of Nutari or Nutemia may not be acceptable (ex. some potted plants).  

 

Entofood: Ephestia kuehniella (sterilized flour moth eggs) and Artemia spp. (brine shrimp) 

This supplementary food source is used for the buildup of predatory mite and predatory bug populations. Predatory mites feed on the brine shrimp and the predatory bugs feed on both the sterilized flour moth eggs, as well as the brine shrimp.   

 

Artefeed: Artemia spp. (brine shrimp) 

This supplementary food source is used for the buildup of predatory mite and predatory bug populations, it is more commonly used combined with feeder mites in our Nutemia product.  

 

Mesofeed: Pollen (Typha angustifolia or Narrowleaf Cattail pollen)  

Pollen is used for both predatory mites and predatory bugs, but is considered a questionable supplementary food source, as it has more cons than pros. The biggest disadvantage when using pollen as a supplementary food source is the possibility of your thrips population increasing, specifically WFT or Onion Thrips. Pollen is not found to support the population of Poinsettia Thrips (Echinothrips americanus).  

A few other disadvantages include:  

• Pollen containing pesticide residue, if not sourced properly. Pollen feeding products typically come from wild harvested typha sp. (Bullrush) so can inadvertently be a source of pesticide or heavy metal contamination to your crop if not from a reliable source that tests all batches of pollen. 

• Pollen’s nutritional value will break down over 3-4 days, due to the pollen sitting on the leaf surface being exposed to sunlight.  

• Pollen does not fully support the beneficial insects nutrition. Predatory insects need protein to reproduce and lay eggs.  

• Pollen can mold in crops under high humidity conditions.  

• Rates of thrips predation by A. swirskii can be reduced by 50% when pollen is present. 

• Pollen can create extra labor costs. When placing pollen in your crop, a specific pollen blower is needed to introduce this food source. It cannot be introduced together with predatory mites, like Nutari and Nutemia can. 

The last important note with pollen is that there is no point putting this supplementary food on crops in full bloom, like peppers. Pepper flowers are already a highly nutritious source of pollen. The only time it makes sense to place pollen out in peppers is right at the beginning of the crop when there is a gap in flowering and there is no pollen (first 6 weeks).   

 

How to Apply Supplementary Food?  

• Consult with Experts: seek guidance from us – sales@koppert.ca. We can provide valuable insights and recommendations tailored to your specific environment and pest challenges.  

• Identify Targeted Beneficial Organisms: understand the specific beneficial organisms that can assist in controlling the pests in your crop. Research their nutritional needs and preferences to determine the most suitable supplementary feeding products. 

• Follow Application Guidelines: proper application methods, timing, and dosages are crucial to maximize these products' effectiveness and minimize any potential negative impacts.  

 

By providing additional nutrition to beneficial organisms, growers can enhance their population, improve pest control efficiency, and promote a healthier ecosystem. While supplementary feeding does come with some considerations, its long-term benefits can make it a valuable tool for sustainable pest management. By understanding the available products, weighing the pros and cons, and applying them effectively, growers can embrace this approach to cultivate thriving crops while minimizing environmental impacts.