Discovering a plant heavily infested with thrips is always a grower’s nightmare. If not treated immediately, pests can easily diminish the quality of the plants, reduce its yield, or worse – kill it entirely.
What Are Thrips?
Thrips are common pests usually found in gardens and greenhouses. These insects are slender, black or straw-colored with two pairs of wings belonging to the order Thysanoptera. Commonly found on the underside of leaves, the critters pierce the plant tissue to feed and lay eggs.
Measuring no more than 1 mm, even an adult thrip is very tiny. For this reason, it is difficult to see one especially during early stages of infestation. Growers should not be fooled, though. While extremely small, the minuscule insect is very active and feed in large colonies. If left untreated, it does not take long before this pest can level an entire garden.
Thrips can mature from egg to adult in 19 days. In higher temperatures, though, it can be as short as 13 days. Once full-grown, the insect can live up to 30 days.
A thrip population can grow incredibly fast as females can reproduce asexually. Adult fems insert their eggs into the tissue of leaves and stems of plants during spring. Each female lays up to 80 eggs which hatch in a matter of few days.
After a few more nymphal stages, the larvae will drop to the ground where to pupate and mature. Fully developed thrips jump or fly back to the plant to repeat the cycle. Because of this fast reproduction cycle, there could be 12 to15 generations of this breed of insect in just a year.
Thrips thrive on plants like cannabis by piercing the leaves and sucking the contents of the plant cells. Such diet robs the flora of the necessary nutrients that it needs to flourish. During the early stages of infestation, small, dark green spots may be seen appearing on leaves. These spots may turn white or silver as the outbreak becomes widespread. As a result, afflicted plants may suffer from stunted growth. Severely affected leaves are also prone to withering and collapsing when water stressed.
Apart from these effects, thrips may also bring something more sinister to plants. These pesky critters are important vectors of a group of viruses called tospoviruses. Among the common viruses the insect transfer to plants are:
- Capsicum Chlorosis virus
- Chrysanthemum stem necrosis virus
- Groundnut ringspot virus
- Impatiens necrotic spot virus
- Irish yellow spot virus
- Maize chlorotic mottle virus
- Tomato spotted wilt virus
The effects of these viruses range from spotting and withering of the leaves to the decay of the veins of the plant. On mature plants, this can cause reduced yield and stunted growth. Per contra, on younger plants, these viruses are frequently lethal.
Identify A Thrip Infestation
It is crucial to identify early on if there is a presence of thrips in a garden or grow room. Here are some ways to determine if there is an infestation.
- Place some yellow sticky straps on the underside of the leaves and the soil. If the plant has thrips, chances are some of them would get stuck in the straps.
- Look out for dark green spots and silvery stains showing up on the surface of the leaves. These are usually the signs of an infestation.
- Thrips usually camouflage themselves by resting parallel to the leaves’ veins. This, along with the fact that they are tiny, makes it hard to spot them. When searching for thrips, be on the look for small movements.
- In the advanced stages of an attack, the leaves of the plants become brittle due to the loss of chlorophyll.
How To Eliminate Thrips Naturally
Thrips may be frustrating to deal with. The sheer number of the pests’ population alone can make most growers want to spray an entire can of pesticide all over the garden.
It is, however, not a good idea. Chemical pesticides contain toxic substances that can be dangerous not only to the plant but also to humans. In a 2013 study published in the Journal of Toxicology, researchers found out that users can inhale pesticide residues on cannabis through the smoke. The toxins in the pesticide may result in various health complications.
Fortunately, there are many other natural ways to combat thrips without relying on synthetic pesticides. These pest control methods prevent the said type of insect from devouring a plantation without compromising the health of the plants, the users, and the environment.
Benefits Of Natural Pest Controls
While chemical pesticides deliver a certain level of effectiveness, these pest control methods are more detrimental in the long run. That is why more and more growers are turning to natural and organic methods in safeguarding plants from unwelcome dwellers.
- Safe. A core advantage of natural pest control methods is that it does not involve chemicals that may ultimately harm the plant and even the grower.
- Environmental. Organic pest control methods not only benefit the plant and the grower, but also helps keep the environment safe. Unlike pesticides, natural means do not spill harmful chemicals in the soil and waterways.
- Long-lasting. Chemical pesticides are useful, but they can only do so much. After some time, they become less effective as pests develop resistance. Natural pest control methods, on the other hand, can stay active for a longer time.
- Cost-effective. According to a study conducted by the Montana State University, for $1 invested in biological pest control, an average of $32 returns in benefits. Meanwhile, chemical controls average only $2.50 in benefits for each $1 invested.
Natural Pest Control Methods Against Thrips
With all the potential harm chemical pesticides may deliver, using organic pest control methods is clearly an option worth considering. The following approaches will help growers deal with a thrip attack effectively without sacrificing the quality and health of the plant.
While most pests come in the form of insects and bugs, not all critters bring trouble. Quite the opposite, many of them are of great help to growers. These beneficial creatures keep a plantation pest-free by hunting down the harmful ones. Essentially, it is letting Mother Nature do her work.
When employing these serviceable insects, it is essential to determine the ones grower wants to get rid of first. Identifying the pest will help a grower choose the most suitable beneficial insect. Here are some of the most apt insects for managing thrip infestation:
- Green lacewings
- Minute pirate bugs
- Predatory mites
Spinosad is a natural insecticide derived from the fermentation of the species of bacteria called Saccharopolyspora spinosa. It attacks the central nervous system of pests, effectively killing them shortly after ingesting the insecticide. On top of that, it has no side effects on the plant itself and also does no long-term harm to beneficial pollinators and insects.
Pyrethrins are an insecticidal compound used obtained from the dried, ground flowers of Chrysanthemum. Pyrethrin-based insecticides are not toxic to most mammals, making it one of the most recommended pest-control substances.
One major drawback of pyrethrins, however, is that it can be extremely poisonous to pollinators and other beneficial insects. To limit this disadvantage, here some pointers to keep in mind.
- Do not apply pyrethrins while plants are blooming
- Only spray in the late evening, night, or early morning
- Do not use the insecticide while there is wind
- Do not apply pyrethrins near beneficial insects’ nests and hives
Diatomaceous Earth, or DE, is a grayish white talc-like powder from the fossilized remains of marine phytoplanktons. It pierces the exoskeleton of the pests, causing the insects to lose fluid eventually die. While lethal to pests, DE is entirely harmless to humans and poses no side effects even when consumed.
When applying DE, it is crucial to scatter it not just on the plant but also on the surrounding soil. It ensures that dormant nymphs pupating in the ground will also be taken care of. DE should also be reapplied after every rain or watering as it gets washed away with water.
Those with the luxury of a larger growing area can make use of the extra space by bringing in companion plants to repel thrips. Utilizing these floras is a proactive approach, as it helps prevent an infestation before it even starts.
The most common and effective plants against thrips include:
Mother Nature Knows Best
Cannabis is a wonder plant. It is no surprise that not only humans enjoy this fantastic herb. The problem, however, is that other creatures who are fond of the flora may end up destroying it. And, that is when growers need to step in.
When battling thrips, it is essential to consider the repercussions of the methods growers would use. Chemical pesticide may provide immediate results but will take its toll eventually. Organic pest control methods, on the other hand, offers the same effect but with little to zero offshoot. Plus, the variety of natural options available helps growers find the method best suited to their needs.