For growers and IPM advisers, reducing reliance on synthetic pesticides is a clear goal—but some pests make this especially difficult due to traits that reduce exposure to natural enemies or control products.
Several key pests have evolved behaviours or physical adaptations that compromise biological control. Here's a snapshot:
Frankliniella occidentalis (Western flower thrips) feeds and reproduces deep within flowers and folded leaves, sometimes limiting access for predatory mites like Neoseiulus cucumeris.
Planococcus citri (citrus mealybug) is covered in a thick wax layer that inhibits both contact sprays and parasitism, while Tetranychus urticae (two-spotted spider mite) spins protective webbing.
Aphids can also prove troublesome. In lettuce, Nasonovia ribisnigri hides between inner leaves, avoiding predators and parasitoids and in peppers Macrosiphum euphorbiae (potato aphid) drops off plants at the slightest disturbance, escaping control agents before they can act.
Some pests are even more challenging due to concealed life stages.
Drosophila suzukii lays eggs in ripening fruit, where larvae develop internally and remain shielded from most treatments.
Dasineura oxycoccana (pepper gall midge) causes internal galling in capsicum fruits and stems; larvae feed undetected until deformities or fruit loss occur—often too late for intervention.
These biological defences—whether behavioural, structural, or lifecycle-based—can undermine even robust IPM programs. Effective management depends on early detection, crop scouting, and well-timed integration of control strategies that account for pest biology and vulnerabilities.
We'll be posting more on this subject in the future. But in the mean time why not try look at our mealybug courses here
Which pests are proving most difficult in your system—and how are you adjusting your IPM tactics to match?
