Focus on News

Fight against diseases and pests of trees

Despite our attention trees can be affected by diseases or pests and get sick ruining their aesthetics, they waste away and in some cases die. The main pests of plants can be divided into the following groups:

  • animal parasites
  • plant pests
  • viruses and similars

boboli_fontana_del_tritone_stoldo_lorenzi_03This will include also many “useful” insects that produce a biological control of harmful species. Therefore, in order to respect the environment, human health and the natural balance of ecosystems, carefully interventions designed to identify the best time they are studied and planned and counteract the harmful agent.

The animal pests attack the plants and the fruits in several ways: by sucking sap by pricking the plant tissues with the stiletto mug; due to erosion by destroying the plant tissues with their chewing apparatus

All this causes mainly two devastating effects:

1) intracellular parasitism or removal of lymph between all ‘internal cell tissue forming yellow blob

2) occlusion of vascular bundles with clogging in the same zones that. Block the passage of the sap.


Type  Cause  Symptoms  Remedies
Botrytis Heat, humidity, water excess whitish or black spots, rot Avoid watering in the vicinity of the stem
Chlorosis Lack of iron and manganese, nitrogen and magnesium, excess water Yellowing of leaves Fertilize the plant
Sooty mold poor ventilation Fouling dusty and blackish on the leaves Wash the leaves with warm water, or water and milk
Powdery mildew Environmental humidity high, irregular watering, drops in temperature Storage dusty or whitish Improve and correct the culture conditions
Rust Excess moisture, inadequate temperature orange spots, reddish or yellowish, warts Remove damaged leaves and stems


MITES Leaf remover
APHIDS (plant lice) Weakening discoloration distortions deformation honeydew sooty mold Pine, spruce, acacia, maple, cedar, cypress, elm, linden, camellia, ivy
COCHINEAL (wad) Foliar yellowing leaves sticky Defoliation Pine, wisteria, juniper, ficus
COCHINEAL POWDER Bleaching leaves leaves sticky Defoliation dieback branches Palm, ivy. Ornamental plants
WHITE FLY Enmeshment Yellowing leaves leaf Slowdown flowering sooty mold Ornamental plants
RED SPIDER Discoloration cobwebs Defoliation Azalea, Camelia maple, elm, pine and fruit trees
Psyllid Desiccation Fall leaves and buds honeyed Albizia
Thrips blacks dots on Yellowing leaves and fall dieback Deformation Discoloration Ornamental plants
Leafhopper Foliar browning and desiccation
Phylloxera Damage tuberosity roots Yellowing leaves and deformation Redness on the foliage dry yellow circular areas on the leaves Holm, oak tree
METCALFA PRUINOSA Weakening sooty mold contamination secretive
LARVAE stripper O leaf-rollers Braiding leaves with silky threads
SNAILS Weakening foliar fungal diseases leaf removal
Bark beetle under the bark Yellowing leaves leaf removal Spruce
Gypsy moth Browning leaf defoliation Oak, birch, chestnut, hornbeam, beech, maple, poplar
Ants  leaf defoliation Fir, acacia, maple, cypress, elm
NERATOSE roots Ornamental plants
Bark beetle OAK Holes on the trunk and tunnels under the trunk Oak tree
TINGIDE AMERICAN yellowing leaves plane tree
GALERUCELLA Weakening, leaf removal Olmo
Red Palm weevil Leaf removal Pine
Pine processionary Weakening, leaf removal Pine
Oak processionary Weakening, leaf removal Oak tree
Cimex Defoliation Alteration of chlorophyll Poplar, willow, hawthorn and fruit trees
Chrysomela Defoliation, slowing growth of lignification Poplar, willow
Budworm Green Defoliation, rolling leaves Oak tree

We will examine below in more detail some of the most common pests: pine processionary, aphids, cochineal.


Name: Traumatocampa (= Thaumetopea) pityocampa

Family: Thaumetopoeidae

Damage: This moth attacks all species of pine, but especially the black pine (Pinus nigra), Scots pine (Pinus silvestris), the maritime pine (Pinus pinaster), the Aleppo pine (Pinus halepensis) and various species cedar.thaumetopoea_pityocampa

Description of the damage: The larvae feed voraciously of pine needles also causing defoliation of strong entity. Severe attacks can weaken the plant causing developmental delays. The stinging hairs of the larvae can cause skin irritation, eye and respiratory.

Natural enemies: the moth has several natural enemies, especially some Hymenoptera calcidi oofagi that, while having a significant role in limiting populations, fail to curb pullazioni.



Aphids are insects known as “plant” lice infesting nearly all ornamental plants, both indoor and outdoor, as well as the crops of agricultural interest. The adults, long from one to four millimeters, are covered with a thin integument of light yellow or green, or gray, or black. Some are winged forms that can migrate from one plant to another, reaching new plant hosts up to hundreds of kilometers away. The forms do not winged (wingless) instead, after losing his wings, focus all their resources in reproduction, thus giving rise quickly in crowded colonies. acyrthosiphon_pisum_pea_aphid-plosAphids have great capacity for adaptation, especially in temperate climates. The plants can be attacked by different species, more or less frequent and dangerous, olifaghe or polyphagous (that feed on a few species or many), and often able to become resistant to insecticides. Fortunately, these pests have many natural enemies and it is on these antagonists that you are relying to contain infestations below the economic damage threshold in biological control programs.

Symptoms on plants: Aphids in addition to cause direct damage to the removal of lymph and with the emission of saliva that causes physiological changes, produce serious indirect damage as they are capable of transmitting the virus by feeding many of the infected plants first and then passing those healthy.



The Saissetia oleae (Oliv.) Also called “half peppercorn” for its emiglobosa form characterized by an H-back relief and for the dark coloring, cochineal is the most widespread and damaging of olive groves, but being polyphagous can develop at the expense of many plants of agricultural and ornamental interest.olivier_cochenille-noire1

Damage: Causes direct damage with the subtraction of sap and one indirectly caused by the release of honeydew. The latter is deposited on the underlying vegetation and favors the development of saprophytic fungi, crusting branches and leaves, reduces photosynthesis and gas exchange, causing a slow decline of the olive trees that causes a general decrease of the vegetative activity, resulting in poor flowering and fructification. It is essential before starting any type of treatment to identify the disease or parasite and then eradicate them adequately.

The plans disinfestation eliminate pests and parasites, but protect the flourishing of plants. The substances are spread by means of pumps and variable jet atomizers or nebulizers: formulations, usually aqueous emulsions, indicating on the label use in green areas, usually they have persistent activity and very low toxicity. Adequate and cyclical interventions avoid unpleasant new infestations. Rely only qualified personnel to quickly eliminate infestations and limit as much as possible to the economic damage caused by eventual death of the plant or crop loss.


Mario Alessi