How to control whitefly in your garden
Typically our gardening journey starts like this.
You get all motivated and start your long-pending garden. You start the seeds; the seeds germinate! You whistle around. They plants continues to grow. Woohoo! .One fine day you see a tiny insect running around in your plant. Next couple of days, they become more prominent and a week later, the pest seems to have taken control of your sweet garden!
Pests! Just the word gives us jitters. Like all gardeners, I have hated them all my life. (I know, I know they are part of the environment we agreed to coexist in and all that).
Once you spot a pest, usually, you google around for identifying it or you run to the nearest garden store and explain what you saw… and we all know how that goes!
You: “I have some white stuff on my plant leaves”.
Store: Do you have a picture?
You: No, But its white like cotton it is all over my plant I paid so much and bought. OMG what do I do?
Store: Does it move around? Does it fly?
After a lot of guess work and dumb charades you both come to a conclusion of what pest it is. This is a typical day for me when I visit my store.
So before we begin this post, my sincere request to you all gardeners is “please take pictures of your garden on a daily basis.” . We all have smart phones. Put that gazillion megapixel camera to good use. Especially take pictures of the following
- When the plant it germinates
- When it is transplanted ( if it is done)
- When it flowers
- When you see some abnormalities
- Pest attack.
- Pest damage
- Harvest! (to show off)
When you take pictures on a daily basis, you automatically maintain notes about your garden. Use tools like Skitch add text to your pictures.How is that for a new habit?
Now, lets get to the topic of interest — how to control whitefly?. We are going to discuss about white flies in this post.
Description and Identification of whitefly
Whitefly is one of the most damaging plant pest both in the home garden segment as well as commercial agriculture.There are several types of whiteflies. The most common ones are two types Trialeurodes vaporariorum and Bemisia Tabacii
Whitefly is a small winged insect very closely related to aphids. As the name implies, they have a white colored wax coated wings. They are very small in size about 1-2mm. They are always found on the lower side of the leaves. They suck the sap from the plants and in that process they also infect the plant with viral diseases. The plant may develop spots, lose vigor and eventually fall prey to diseases passed on by these flies.
Simply, walk near the plant and gently move the plants leaves. If you see a swarm of white flies flying around, you have White flies in your garden.
Hang a adhesive coated yellow cards near the plant canopy. Roughly about 1 per square meter. Whiteflies get attracted to yellow color and they fly towards it and get stuck on it. It is a good way to identify the presence of whitefly in your garden or backyard using a sticky trap.
Life cycle of whitefly
Whiteflies develop rapidly under warm weather conditions and their population can reach very high numbers if there are no natural predators for them. An average adult female whitefly can lay upto 400 eggs. These eggs are tiny oblong and is attached to the leaf by a short stalk.
As the whiteflies hatch, the go through four stages before they become an adult whitefly. The intermediate stages are called instars.
Whiteflies – Nymph Stages
- In the first stage, the egg hatches and the larva moves around in the leaf for a few hours and settles in a place. It not only just settles. It inserts its “stylet” (kind of a driking straw if you will) into the leaf and just sits there! After this stage, the insect is immobile.
- In the second stage, they look flat and oval. Very similar to garden scales.
- The increase in size in their third stage.
- The winged adult whitefly emerges.
As you can see in the image below, the spirally laid eggs on the lower surface of the leaf. There are hundreds of eggs in this spiral. If we do regular scouting in the garden and carefully inspect both the sides of the leaves, we can not only identify the whiteflies before they explode in population, but is also easier to control them easily. At this stage, they are immobile.
Whitefly infestation on moringa leaves( Drumstick tree). Smaller leaved trees can pose a problem in individually inspecting the leaves. Finding them early gives us an opportunity to devise a pest management strategy that is safer to the environment.
As the adult female lays the egg, they sometimes hold on to plant part they are feeding on, while moving the body causing a circle to be formed.( I am starting to kind of like them now ;). With in a week, the crawlers come out and find a place to insert their probe and settle. The remain fixed to the plant for 3-4 weeks. Post that period, the whitefly adult emerges to continue this process. It lives for another months time.
Whiteflies feed using a long probe called stylet. They suck the sap out of the leaves( xylem or phloem sap). They are mostly found in vegetable and ornamental plants. After ingesting the sap, they excrete a sticky honeydew. This honeydew becomes a host for black molds. This can also cause discoloration of leaves. This honey dew also attracts ants.
Generally, the whitefly themselves by sucking the sap, dont cause a huge problem. The issue is they transmit diseases and virus vectors in the process. Leaves will get distorted, silvering can happen.
Management of whiteflies and control
“Catch them young” is our motto here. It is much easier to identify and control whiteflies or any pest for that matter when their numbers are manageable.The best way to tackle these pests is to do an integrated pest management. Some of the steps are mentioned below.
- Early identification and destruction of eggs or removal of the entire leaf/affected part. Dispose them carefully.
- Do not plant too thickly. More congested the garden, more the pests.
- Use Yellow sticky traps, to identify and calculate the density of the pests in the area.
- In the initial stages of its life cycle, the insects do not move. It is easier to control something that is immobile. Once they start flying, they will fly when you apply a spray and then will come back when you are done.
- Use neem oil at 5-10ml per liter ( depending on the strength of the active ingredient, follow the instructions on the product). Add an emulsifier, to make the oil mix with water. Like I wrote before, spray is only effective if it hits the insect.
- Ensure you spray on both sides of the leaves. This is a common mistake gardeners make. Spraying only on the upper side of the leaves. Insects like hiding spots. Lower side of the leaves are their best bet.
- Avoid chemical pesticides, they are not effective in the long run. They make the situation much worse by killing the natural predators there are. And the whiteflies are smarter they know all our pesticide brands and have developed resistance towards them. Talk about surviving skills.
- Allow natural predators such as the following to thrive in your garden
- Lady bugs
- Parasitic Wasp ( Encarsia Formosa)
- Beauvaria bassiana ( Fungus that affects many sucking pests and worms). We have this is Garden Guru store.
- Verticilium Lecanii aka Lecanicillium muscarium
If you follow the above said guidelines, we can get the pest under control. Please remember the fact, one cannot completely eliminate them. Attempting to do so will cause more trouble. Just control them to an extent that the damage is not too much and something you can live with. How is that for an environment day finishing! Happy Environment day everyone!
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