The Pine Processionary

Attention, all to the shelters! The processionaries are here! With a preference for black pines from Austria, Scots pines and up to cedars. These charming creatures, whose “cocoons” appear as branches of our pine trees from the end of November, become particularly visible as soon as the days start to grow again.

nid_de_chenilles_processionnaires_du_pinAs soon as the temperatures are milder, the caterpillars leave their nest to devour the needles of the branches on which they have nestled, then reintegrate the cocoon they are closing and which keeps them perfectly protected from the lowest temperatures.

For the record, the company Dupont de Nemours working for NASA, would have been inspired by the construction technique of the nests of processionaires to develop the first nonwoven textiles. Textiles extremely resistant to rips and temperature variations.

processionnaire_ligneDespite their ingenious builders’ abilities and their fun way of following each other in their own right to bury themselves in the vicinity of their tree between February and April, these caterpillars represent a significant danger for the health of people and animals that can cross their route. Indeed, the caterpillars are covered with stinging hairs, which are detached and can cause in humans and animals to the best itching uncomfortable, but mostly skin or internal allergies after inhalation, with consequences more or less serious. Some cases that may lead to hospitalization and death of the affected subject and more particularly animals (dogs, cats) having the bad idea of ​​eating caterpillars or putting their muzzle in the wrong place.

The breeding of these animals varies according to cycles. It is difficult to get rid of it other than physically by cutting the infested branches in winter, then destroying the nests by fire (it is absolutely forbidden and particularly unconscious to deposit the cocoons in garbage bags and simply throw them in garbage. ).

processionnaire_papillons_malesHowever, in recent years, pheromones traps have been found in all good garden centers: a sort of wasp traps in which a capsule containing female butterfly pheromones is deposited. Placed at the right time (between June and August) these traps attract the male butterflies which are thus captured and can not fertilize the females who will seek elsewhere a partner or will not be fertilized thus limiting the proliferation.
Sprays of pine trees with a decoction of Bacillus thuriengiensis can also be sprayed after the summer laying or when the nests appear. This treatment is a little more random because the bacillus must still be present on the needles when the caterpillars are hatched and begin to eat the needles in late summer. Later treatments will also be random if it is cold after spraying, the caterpillars remaining warm in their cocoons.

geaides_che0302nesIn our experience, traps set at the right time are very effective and can limit populations for a good dozen pines on a radius of 500m.



Knowing the needs of your lawns and lawns at any time of the year can help you better manage your efforts to achieve a result that meets your expectations. Knowing when to apply fertilizer and various treatments will help you limit interventions with the best possible results for this very particular crop. We detail below, season by season the interventions to be made and the things not to do for obtaining a beautiful lawn.


For the Grenoble region, from the end of February to the end of March, the melting of the last snow and the warming of the temperatures gives the lawns a fresh green color. During the spring, shoots reach the end of their life cycle. They will draw on nutrient stores stored in late fall to produce flower stems. This flowering process is not generally noticeable due to clippings that eliminate flower stems.
Do: * Rake and gather all leaves and debris on the lawn to allow better warming of the soil and better air circulation.
* Wait for the first clippings until the grass grows actively and reaches a satisfactory height of mowing between five and nine centimeters.
* Remove weeds manually or by heat treatment. At the time of their flowering dicotyledons such as dandelions use their food reserves, their restart will be limited.
* Start watering when your lawn has drying out symptoms. Water copiously to allow the water to penetrate deeply into the soil and thus create the conditions for deep rooting. Water at irregular intervals, taking into account the rains.
* If you noticed in the previous fall that your lawn has symptoms of dicotyledonous invasion, you can intervene by spreading or spraying a selective germicidal weed killer at mid-season, usually between April 15 and 20 may. Try to limit your interventions to the most affected parties. Manual weeding is less dangerous for the health of all (plants, soil, water, animals and humans).
Do’s and Don’ts: * Unless you have a very high quality lawn, you do not have to add fertilizer at this time of year. If you think it is necessary, bring 30 grams per square meter of a fertilizer with a ratio of four units of nitrogen for one unit of phosphorus and two of potash.
* Unless your lawn is suffering from a particularly high ground-breaking problem that prevents the grass from growing, do not scarify in the spring. This practice may simply expose more bare soil surface to the combined action of the sun and rain and further increase soil growth while promoting germination and weed growth.


During the summer, when temperatures can reach 40 ° C in our region, the most fragile grasses slow down their growth. This is the time to take care of the good health of lawns without promoting excessive growth.

* Raise the mowing height a good centimeter at 5-6 cm. High mowing will help your lawn cope better with seasonal stress and will limit sprouting and emergence of summer weeds by increased shade. Insignificant mowing waste can be left on the ground, except to form windrows that are too thick.
* If you want to maintain a very green and active lawn throughout the summer, you will need to bring 20 to 40 liters of water per m2 per week in one or two times in the morning to avoid the development of fungal diseases due to the combined action of moisture and heat when watering in the evening. Light soils (sandy or stony) require larger amounts of water than heavy soils (clay). You can also condition your lawn to better withstand the heat of summer by gradually reducing water intake to bring 10 liters of water per m2 every ten days.

* After a last limited fertilizer supply of 30 grams per m2 at the end of June it is better to avoid fertilizer intake in summer. This will allow the grass to grow slowly without drawing too much in its reserves.
* Do not plant at this time. Your lawn may appear sparser at this time because of its naturally smaller growth and density. Adding seed to improve the appearance of turf at this time only puts young shoots under stress due to heat and summer diseases that they do not support. The additional water required by such seedlings can be very expensive.