Illeis galbula – or otherwise recognised as yellow and black ladybirds – are bugs that eat fungi and powdery mildew on our plants. As gardeners, we look at them and they bring joy to our hearts, being the lovely ladybirds they are.
BUT did you know that these ladybirds cause more harm than good on our zucchini, squash, cucumber and pumpkin plants, all part of the cucurbitaceae family?
What’s the problem caused by these ladybirds on my zucchini, squash, cucumber and pumpkin?
They come to the plants infected with powdery mildew to feed and then they proceed to spread the fungus from plant to plant, infecting with the disease as they go.
If you have many zucchini and only one has powdery mildew, WATCH OUT! With these little creatures, they can all be infected by the end of the week!
After the ladybirds are full and sated, they travel on their merry way to the next plant, regardless of whether or not they still want to feed. As they walk along the plant, they drop a few mildew spores on their way thus infecting the plant.
Where do these pesky ladybirds come from?
The females lay small groups of white eggs on the underneath of the fungi-infested leaves, which you may observe are a pointed shape egg. From these eggs, the larvae nymphs hatch and deceptively look nothing like you might imagine would grow to be ladybirds…!
When hatched, it attaches to the leaf and moults into a pupa. Adults hatch from the pupae and immediately mate.
The length of time of each life cycle is very dependent on the outside temperature – the hotter it is the quicker they will multiply.
How can I organically control these ladybirds around my zucchini, pumpkin and squash plants?
Interestingly enough, birds are not attracted to these bugs due to their bright colour. More to the point, they are quite bitter, so birds are very wise to not eat an unpleasant meal.
The best way to control these pests is by preventing powdery mildew on your plants.
What is your secret recipe for controlling powdery mildew organically, you ask?
Organic recipe #1
In the early stages of this fungal disease, you can spray the plant with a milk and water mixture (recipe: 60% water to milk, shake well) on all parts of the plant. The milk has natural antibiotics which, when exposed to sunlight, can act as a natural fungicide.
Top tip: Remember to spray first thing in the morning before the heat of the sun, and then repeat on a daily basis until the spores are no more.
Organic recipe #2
Baking soda (sodium bicarbonate) works really well too, as it creates an alkaline environment on the leaf and increases the pH by 1 which is enough to kill or prevent all spores.
Mix 3 tablespoons of baking soda into 4 litres of water; add 1 tablespoon of oil and 2 drops of natural dishwash liquid, mix together and spray all over the plant until dripping.
Bonus tip: Cider vinegar and Effective Microorganisms work in very similar ways by altering the pH so the spores can’t live.
Next week, we will talk more about the pests and disease of zucchini so you can protect this delicious and versatile summer crop. And don’t forget to get in touch with any questions, tips or tricks of your own! I love to hear from you.