Fundecitrus publishes information about the relationship between sprouts and psyllid

Over the years, Fundecitrus research has managed to obtain a lot of information about the role of shoots and the behavior of both the psyllid and the greening bacteria, fundamental knowledge for the development of efficient management strategies. Check out some of this information:

What is sprouting?

It is the process that leads to the emergence of new tissues (shoots), normally at the ends of branches and plant crowns.

Why are psyllids attracted to sprouts?

Because the shoots are where psyllids feed and reproduce. They are attracted to the color, which is light green, contrasting with the dark green of mature leaves, and volatile chemicals.

Why do sprouts favor insect feeding and reproduction?

Because they have layers of cells with thin walls, which facilitates the penetration of the stylet (mouth apparatus) of both the adult insect and the nymph, which is the insect's life phase that occurs shortly after the eggs hatch.

What is the relationship between the level of softness of the bud and the number of nymphs that reach adulthood?

As the bud matures, its tissues become more rigid, making it difficult for the nymph's stylet to penetrate and hindering the insect's feeding. Therefore, many die and do not reach adulthood.

What stimulates the emergence of new shoots in plants?

The age of the plant, the climate and pruning practice. Young plants that have not yet started to produce fruit send out shoots almost all year round. Adult plants produce shoots at different times, stimulated mainly by the occurrence of rain and temperatures above 20°C. Pruning the sides and top of plants is also a great stimulator of sprouting. Furthermore, the plant needs good nutritional reserves as a physiological condition for sprouting.

What are the favorable conditions for growth and how much do the shoots grow per day?

To grow, sprouts also depend on soil temperature and humidity. For example, between 22 and 25°C and with moist soil, shoots can grow, on average, 1 cm to 1,5 cm per day, and under higher temperatures they can grow up to 4 cm per day.

What are the most favorable stages of the bud for the psyllid to feed on?

The most favorable phases for psyllid feeding are the shoot growth phases (V2 to V6). At these stages, the shoots are softer with the presence of small, rapidly expanding or fully expanded leaves. The V7 phase, when the leaves are fully mature, is less favorable, but still serves as food for the insect.  

How does the psyllid transmit the greening bacteria?

The transmission is divided into three stages:

How does the bacteria move around the plant?

The bacteria move, carried by the flow of phloem sap, which goes towards the growing parts, such as new shoots and roots. This movement contributes to the spread of the disease because the bacteria is taken to the buds, where the psyllid usually feeds.

What factors contribute to psyllid dispersal?

Disturbance or ripening of shoots encourages the psyllid to migrate to other plants, and increased temperature and low air humidity induce the insect to disperse. Winds favor their dispersion over longer distances and also indicate the direction of migration.

Psyllid management strategies: In this webinar, Fundecitrus professionals talk about the moment of high population and how to control the insect. Watch by accessing here.