Greetings, human caretaker. From my perspective as a collective of Calibrachoa plants in your care, the appearance of holes in our flowers and leaves is a clear signal of distress. It is a language we speak through our physical form, indicating that our well-being is being challenged. The causes are typically external and biological. Let me explain the most common culprits from our point of view.
This is the most frequent complaint we have. The damage appears as large, irregular holes chewed right through our tender petals and foliage. The primary offender is often the tobacco budworm (*Heliothis virescens*). Their small, green caterpillars are particularly fond of burrowing into our unopened flower buds, hollowing them out from the inside before you even see the bloom. If you notice small holes with dark, pellet-like frass (excrement) nearby, it is almost certainly their work. Other caterpillars might also find our leaves a palatable meal, leaving behind similar damage. From our perspective, this is a direct attack on our reproductive organs (flowers) and our solar panels (leaves), severely hindering our energy production and our ability to attract pollinators.
While these insects don't create holes in the traditional sense initially, their feeding activity can lead to a similar outcome. Aphids cluster on our succulent new stems and the undersides of leaves, piercing our tissues to siphon out our vital sap. This weakens us significantly. The damage they cause often results in distorted, curled growth that can tear and create holes. More importantly, they excrete a sticky substance called honeydew, which encourages sooty mold to grow, further blocking our sunlight absorption. Thrips are even more subtle; they rasp at our petals and leaf surfaces, causing a stippled, silvery effect that eventually causes the tissue to die and fall out, creating a pin-prick hole effect, especially on our delicate flowers.
Although less common than pest damage, certain environmental conditions can mimic the symptom of holes. If water sits on our petals and leaves under intense, magnifying sunlight, it can act like a lens and cause small burn spots that may eventually tear and form holes. Similarly, very heavy, pelting rain or hail can physically batter our soft tissues, punching literal holes through them. While we appreciate your care, overly vigorous handling during transplanting or maintenance can also accidentally bruise and tear our stems and leaves, creating wounds that look like holes. We are resilient, but we are also delicate beings.
Finally, what may start as a small lesion from a fungal or bacterial pathogen can expand into a hole. Diseases like Botrytis (gray mold) often begin as water-soaked spots on petals or leaves. As the infected tissue dies and dries out, it can fall away completely, leaving behind a hole with a tell-tale ring of discolored, decaying matter around its edge. This is a sign that our internal systems are fighting an infection, and the hole is a scar of that battle.
