Tingids, or lace bugs, belonging to the family Tingidae, are parasitic insects within the order Rhynchota. Italy hosts various species of agricultural interest, characterized by their morphological features, life cycle, and the type of damage they inflict on plants. In practice, they are distinguished by the type of crop they attack. Nevertheless, tingids are troublesome parasites due to their tiny size, making them difficult to detect. They can cause significant damage to fruit trees and ornamental plants, both aesthetically and physiologically.
In this article, we will explore how to defend crops from infestations using biological methods.
Description of Tingids
Tingids are small parasites, measuring about 3 mm in length when adults. They have a pronotum with both lateral lamellar expansions and a triangular extension that covers the scutellum. Their head is very pronounced compared to the rest of the body. The wings (elytra) feature a complex reticulation, giving the insect a honeycomb-like appearance. The front legs are attached to the posterior edge of the prosternum. They have two segmented tarsi and lack arolium. Their coloration varies depending on the species, ranging from cream to brownish to blackish.
Relevant Agricultural Tingid Species
Here are the tingids to keep an eye on in Italy and the agricultural crops they infest:
- Stephanitis pyrioides: Attacks rhododendrons and azaleas.
- Corythucha ciliata: Affects plane trees and also attacks ash and lime.
- Stephanitis takeyai: Targets Japanese andromeda (Pieris japonica).
- Stephanitis pyri: Attacks pears and other fruit-bearing and ornamental plants such as apple, cherry, plum, pyracantha, rose, rhododendron, azalea, hawthorn, and hawthorn.
- Corythucha arcuata: Infests oak trees.
- Monosteira unicostata: Affects almond and poplar trees.
Damage Caused by Tingids
The damage caused by tingids is common among the various species listed above. Both the young forms of the parasite (nymphs and nymphids) and adults live and infest the undersides of leaves. Through their feeding punctures, they cause typical depigmentation on the vegetation, affecting much of the leaf blade. Heavily infested leaves lose their lymphatic exchange and ornamental function, eventually withering and falling prematurely. Upon close examination of the undersides of leaves, you can observe small, dark, bituminous droplets, which are the excrement of the tingid. In general, the foliage becomes soiled, and the damage on the underside can easily be confused with sooty mold. On the upper side, discoloration is similar to that caused by the red spider mite. The fruits can also be soiled by the parasite’s secretions. In ornamental trees near homes, the parasite can find its way indoors, causing problems and discomfort.
Tingids overwinter as adult insects, sheltered in soil crevices and vegetation, such as under tree bark or branches. In spring, typically in April, they resume their activity by emerging from their overwintering sites and beginning mating. The eggs are laid on the undersides of leaves, along the midrib.
The egg’s development time varies from 20 days to one month, while the development of new adults takes about 20 days. Multiple generations can occur in a year, considering that overwintering starts in October.
Eliminating Tingids through Organic Methods
Biological defense against tingids begins with monitoring their presence, requiring careful observation of the leaves. The upper side is highly discolored, while the lower side is even soiled by the parasite and its excrement. To biologically eliminate tingids from plants, the most effective products are those based on natural pyrethrum, available in specialized stores.
These products do not require the license required for phytosanitary products. It is advisable to thoroughly wet the vegetation, taking care to target the undersides of leaves, where the parasite is active. After treating with natural pyrethrum, follow up with a wash using potassium soft soap to clean vegetation soiled by the parasite’s excrement.
These interventions are most effective when performed in spring, targeting the first generation of the parasite, which is, however, the least visible.