Aquaponics systems, being organic in nature, can encounter insect and pest attacks just like any other type of farming. However, pest control in aquaponics follows a similar approach to conventional farming methods, albeit in a more organic manner.
One way to manage pests in aquaponics systems is by regularly using organic pesticides like neem oil extract, which can be mixed at a rate of two tablespoons per gallon of water. Additionally, mechanical barriers such as nets, manually removing pests, or employing beneficial insects are alternative methods of pest control.
In aquaponics systems, various types of pests have the capability to impact plants. The process usually begins with a discreet initiation, and gradually progresses until the entire crop is completely eradicated.
It is crucial to have a defense system in place in case pests attack, in order to protect your aquaponics system. Additionally, other preventive measures can be employed to hinder pests and insects from infiltrating and causing damage to the entire system. In this article, we will elaborate on the different methods of control and their effectiveness.
Why we rely on commercial products over homemade remedies
Garlic, chili, and vermicompost-based concoctions are commonly used by aquaponic practitioners and can be effective for certain pests. However, after trying various home remedies, we now solely depend on commercial products. As commercial producers, we cannot afford the time and effort needed for homemade remedies or the risk of using less effective controls. Therefore, we rely on commercially available products that have been extensively studied and provide reliable information on their impact on our aquaponic system. These products have proven their ability to eliminate and manage pests based on our experience.
OMRI-certified pesticides and IPM
Our main focus is on organic pesticides, the majority of which have received certification from OMRI (Organic Materials Review Institute). This is mainly due to the fact that most commercial aquaponic producers cultivate “organic” produce and utilize pesticides that are allowed under USDA Organic Standards. Prior to delving into specific brands and products, I suggest conducting research on integrated pest management, commonly known as IPM.
IPM is an approach to pest control that involves integrating cultural, mechanical, chemical, and biological methods within the broader context of economics, environment, and human health. The principles of IPM encourage a comprehensive outlook on pest control, emphasizing the use of compatible controls and minimizing unnecessary spraying.
Having an IPM strategy is crucial for aquaponic producers due to several reasons. Firstly, it is vital because of financial considerations as IPM is the most cost-effective method for managing pests. Additionally, aquaponic producers face more intricate environmental restrictions compared to typical producers. Moreover, their customers tend to prioritize healthy food, making IPM even more important. Neglecting to implement an IPM strategy can result in unnecessary expenses for pest control, negatively affect the fish and system health, and even jeopardize the well-being of their customers.
Controls diversity is key to sustainability
On our farm, we utilize a combination of controls. It is crucial to maintain diversity in your control techniques to ensure that the pests in your greenhouse do not develop resistance to the controls being used. I have encountered individuals who stick to a single control method for months, if not years. They always claim, “It’s working perfectly and I haven’t faced any issues,” and they might indeed have effective control, at least for a little while longer. However, the unfortunate truth about greenhouse and garden pests is that they adapt rapidly to toxins in their environment and quickly develop resistance to even the most potent pesticides. By employing a variety of control methods and incorporating chemical, biological, mechanical, and cultural controls together, resistance can be prevented from arising.
How growers know the harmfulness of a pesticide to their fish
Pesticide labels usually contain information about LC50, which stands for lethal concentration. LC50 refers to the concentration of a pesticide that causes the death of 50% of the tested population. The tested population typically includes certain fish species, such as trout (Oncorhynchus spp.) or tilapia (Oreochromis spp.). It is important to pay attention to the LC50 for these species. If you cannot find this information on the label or Safety Data Sheet (SDS), you can refer to scientific studies on lethal concentration and that specific pesticide, preferably by using Google Scholar. It is advisable to consider the lowest number provided in these studies.
To locate this value, refer to the label and/or Safety Data Sheet (SDS) of the pesticide in question, as they are commonly listed together.
The LC50 will be listed in the SDS.
The LC50 value is mentioned for a specific duration, and the shortest duration mentioned is 96 hours.
To determine the maximum quantity of the pesticide that can be used, multiply the LC50 value by the volume of your system, expressed in liters.
Let us examine an instance utilizing pyrethrum (type 1 pyrethrin), which is the active component in Pyganic 1.4.
To determine the amount of pyrethrin necessary to reach the LC50 for your system, we observe that the most conservative LC recorded is 0.0014 mg/L (96 hrs; Americamysis bahia) when searching for this number.
Step 1: As an example, let’s consider the Bright Agrotech aquaponic system and multiply the LC50 (96 hr) value by the volume of the system in liters.
To calculate the amount in milligrams per system, we start by multiplying 4,300 gallons per system by 3.79 liters per gallon, resulting in 16,279 liters per system. Then, we multiply this value by 0.0014 milligrams per liter, giving us 22.79 milligrams per system.
In step 2, the next action is to measure the amount of pyrethrin concentration used for mixing and application in the greenhouse.
The label provides a suggestion to combine 1–2 fluid ounces of Pyganic 1.4 with each gallon of water in compressed sprayers, equivalent to 2–4 Tbsp per gallon. In my greenhouse, I can spray the entire crop with 1.5 gallons of mixture, which is approximately 6 Tbsp (or 3 fluid ounces) at the maximum application rate.
According to the label, 59 fluid ounces is the same as 0.05 lbs of pyrethrin, indicating the amount of active ingredient.
When you divide 0.05 pounds of pyrethrin by 59 fluid ounces, the result is 0.0008475 pounds of pyrethrin per fluid ounce.
To convert 0.0008475 pounds of pyrethrin per fluid ounce to milligrams per pound, multiply it by 453592, resulting in 384 milligrams of pyrethrin per fluid ounce.
To calculate the total amount of pyrethrin, multiply 3 fluid ounces/system by 384 mg pyrethrin/fluid ounce, resulting in 1152 mg pyrethrin/system.
The LC50 for the system is much smaller than this number.
How growers keep pesticides used out of the system water
In order to prevent a pesticide from entering the water, it is important to consider the second aspect of utilizing LC50. Regardless of the careful use of LC50, it is always advisable to prepare backup plans. By applying pesticides correctly and ensuring that water surfaces are protected from exposure, it is possible to avoid reaching the maximum allowable pesticide concentration in the water system.
1- Correct use of pesticides.
The label of every pesticide provides instructions for its application, including details on the highest concentrations, mixing instructions, safety precautions, and recommended clothing. It is important to note that pesticide labels are legally binding and must be strictly followed. Any use of a pesticide that deviates from the instructions on the label is considered illegal. If there are any uncertainties regarding the application of a pesticide, it is advisable to consult an extension agent, as they are specialized in providing guidance on this matter.
Another important factor in preventing pesticide toxicities is ensuring proper equipment setup.
The proper use and setup of equipment.
Unless the water is exposed in the same area as the spraying, pesticide sprays generally do not enter the system water. The amount of water surface exposed can be reduced by implementing a smart setup. It is difficult for growers who use media beds, Bato buckets, or DWC to separate growing surfaces from water. In these types of systems, you cannot exceed more than 50% of the LC50, and sometimes even that poses a risk. However, for growers who use NFT, ZipGrow, or any equipment with a covering or separator between plants and the media/water, this process is fairly straightforward. For instance, the housing on the ZipGrow Tower provides better protection for the media from coming into contact with pesticides compared to a technique like DWC.
Certain pesticides, such as Azamax and Botanigard, have high LC50 values, making them favorable choices for aquaponics.
How to tell if your fish have been affected by a pesticide
If you are properly monitoring your system, you will be checking on the fish every time you are in your growing environment. By doing this, you will be able to notice any changes in fish appearance and behavior, which can indicate illness. If you are new to farming or unsure of what to look for, here are some general symptoms that indicate fish distress.
- Slow and/or erratic movement. Fish are milling slowly, respond slower than usual to feed, or are erratic in their movements.
- Wobbly swimming and/or convulsions. Fish seem to have lost control, swim at an unbalanced angle, wobble on their axis, or are bending and contracting their bodies.
- Fin extension. Fish fins and gill cover are extended from their bodies.
- Darkening and discoloration. Sometimes discoloration is only evident in muscles under the dorsal fin. If you harvest a fish and notice discoloration while butchering, this could be a sick fish.
- White spots. White spots on the body of a fish are usually indicative of Ichthyophtirius, a common fish parasite, not pesticide toxicity.
- Bloating and raised scales. Again, this is indicative of a disease called Dropsy, not pesticide toxicity.
- Enflamed or disintegrating fins. A sign of fin rot.
- Gulping air. This is typically a dissolved oxygen problem.
- Death.
In case you detect any of these symptoms in one or more fish, promptly remove all the impacted fish and isolate them. Keeping a small tank or container specifically for this purpose is recommended. Cease feeding and assess ammonia levels as it is possible that the issue is related to ammonia toxicity.
If you suspect pesticide toxicity, follow these steps to address the issue. First, consider doing a partial water change. The amount of water you replace should depend on the severity of the toxicity, with 30-50% being a good range. Keep in mind that this sudden change in the fish’s living conditions may shock them. To minimize the impact, use replacement water that has been dechlorinated (or run through an RO filter) and that matches the temperature of the tank water. Additionally, when dealing with toxicity, redo your LC50 calculations. However, before concluding that it is solely a pesticide problem, ensure that there are no other factors contributing, such as zinc toxicity or ammonia poisoning.
How to control pest in aquaponics
When considering crops, the outcome is determined by the inputs. The goal of aquaponics is to create a sustainable organic food source, therefore, it is crucial to ensure that any additives used to control pests and insects comply with organic standards for the system.
The most effective way to control pests in aquaponics is by adopting an organic approach. This involves utilizing plant-derived pesticides that can repel and eliminate any undesirable pests.
The pesticides we use should not have any synthetic chemicals or additives that could potentially end up in the plants and later in our meals.
In aquaponics, the approach to pest control is more precise compared to the various types of pest control available.
The need to continue producing healthy organic food is the driving force behind all methods.
Here are several methods that we have found effective in managing pests within our aquaponics system.
6 methods of natural pest control in aquaponics
- Identification
- Organic Pesticides
- Manual control
- Mechanical control
- Physical barriers
- Prevention
Identification is the process of recognizing or determining the identity of someone or something.
It is important to properly identify the type of insects or pests that are causing the problem in your system, as each pest may require a specific control method.
In order to save time and money, it is important to properly identify pests and insects and efficiently remove and eradicate them. Acquiring organic insecticide is pointless since the issue does not originate from an insect.
Identifying the type of insect causing trouble is easier when you can observe the characteristic evidence left by each pest on plants, as it enables choosing a more cost-effective and efficient method of control.
Organic pesticides are substances used for controlling pests that are derived from natural sources, such as plants, animals, and minerals, and have been certified as organic by a regulatory body.
Neem Oil extract is an example of an organic pesticide made from the extract of specific plants that serve as irritants for insects and pests.
The neem tree seed is where it originates from. This pesticide is commonly utilized and available at agricultural stores or hardware stores.
Is Neem Oil considered safe for use in Aquaponics?
Neem oil is suitable for aquaponic systems as it is organic and will not introduce any undesirable chemicals into the system, therefore ensuring safety.
The drawback is that it will also keep away beneficial insects, such as bees that are necessary for pollinating flowering plants.
By following a step-by-step approach, the neem oil should be combined with two tablespoons for every gallon of water. Consequently, the amount of aquaponic system will determine the longevity of a small bottle of neem oil.
In terms of organic pesticides, ladybugs can be utilized as well. Ladybugs feed on aphids and other small soft-bodied insects, thereby controlling their population.
The use of manual control is an important aspect to consider.
This is the place where you manually eliminate insects that are crawling in your aquaponic system, primarily targeting bigger pests such as grasshoppers, caterpillars, and leaf-eating beetles.
Although this method of control can be somewhat laborious, there are instances when it is essential.
Mechanical control involves step-by-step thinking.
Mechanical control involves the placement of a device or trap designed to ensnare and eliminate insects or pests before they reach the plants.
One way to control flies is to hang flycatchers near the plants. When the flies land on the sticky strip, they become unable to move and eventually perish.
By placing cotton around the base of the posts on which the system is supported and is elevated, it is possible to trap ants and other insects, preventing them from climbing the posts and reaching the plants.
One more technique for mechanical control involves the utilization of a handheld vacuum to suck up any bothersome tiny insects encountered while tending to your garden.
Physical barriers refer to obstacles or obstacles that impede communication between individuals or groups. Such barriers can include distance, noise, and even literal objects or structures that obstruct or limit the transmission of messages. It is important to identify and address these physical barriers in order to ensure effective communication.
Physical barriers range from simply enclosing a small system to shield it from the elements, all the way to constructing a sizable greenhouse to accommodate the entire system.
Even though a greenhouse comes with a higher cost, it provides complete control over the environment, which is particularly beneficial in cold regions with temperate climates.
Using a physical barrier as a method of pest control entails the utilization of netting or similar materials that effectively hinder the entry of any undesired pests into the designated planting area.
Barriers in aquaponics encompass not solely plants but also fish, serving to safeguard the fish tank from pests that could potentially exterminate the entire fish population.
The process of preventing something from happening.
Prior to commencing your system, engage in planning, determine the location for situating the system, and ensure that it is sprayed and treated for ants, termites, and other ground insects.
When your system is up and running, you won’t need to worry about these pests if you think step by step.
When considering general housecleaning, it is important to think in a step-by-step manner.
Regular maintenance is crucial to prevent pests and wandering insects from reaching your plants. By keeping the area around the plants and fishes clean, you can discourage their presence. This requires consistent effort and must be done repeatedly.
By creating such an environment, it also generates a visually appealing and welcoming space for work. Ultimately, you will find it more convenient to operate within the system, avoiding any kind of mess or disorder. This will bring benefits to both yourself and the plants.
