Aculops lycopersici  (Tryon)

Bronzed acariosis  

General

• Tiny mite from the phytoptes group with only 2 pairs of legs. Its maximum size is barely 0.2 mm and it is invisible to the naked eye, especially since it is very slow. It is yellowish-orange in color and is distinguished from other mites by the elongated shape of its body (Figures 1 and 2). They can thus be confused with the hairs present on the tomato.
• Species of worldwide distribution.
• Affects several plants of the Solanaceae family, but it does not cause damage especially on tomato and potato.
• Observed in the open field as well as under shelters.
• Organs attacked : leaves, stems, fruits.
• Symptoms :
  • Brown to bronzed coloration of the leaves (figures 3 and 4), petioles and stems (figure 5) at the origin of the name of this problem.
  • Abortion of flowers (figure 6).
  • Leaves dry out which can lead to plant death when the attack is not controlled (Figure 7).
  • Corky beaches more or less extensive, even cracked on fruit (Figures 8 to 12).

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• Signs  : mites not observable with the naked eye on the affected organs (figures).
• Possible confusion :

Biology

• Development cycle: A. lycopersici shows 4 stages of development during its biological cycle (figure 13): egg, 2 larval stages, and adult.
• The species is maintained on Solanaceae, whether cultivated or not. The life cycle lasts a week in tropical conditions and lengthens in cooler climates.
• Dispersion : by the wind, animals and insects moving in the crop, but also workers and their tools during cultivation operations.
• Favorable conditions : temperature close to 27 ° C and humidity of 30%, in other words hot and dry weather.

Protection

• Control rather difficult because this mite is often detected too late in crops by the first damage it causes (bronze color).
• Weed the crop and its surroundings.
• Disinfect greenhouses and equipment used.
• Check the sanitary quality of the plants before and during their introduction into the crop or shelter.
• Produce the plants in a clean shelter . However, nurseries insect-proof are insufficient to prevent the entry of bronzed acariosis, given their very small size and mode of dissemination.
  
• Reason for  chemical protection, in particular if you use auxiliaries or biopesticides.
• Attempt to eradicate the first outbreak (s) by eliminating the first affected plants and / or locally treating them and surrounding plants.
• Use a large volume of mixture and with sufficient pressure to access the “heart” of the vegetation. The effectiveness of the treatments should be monitored over time.
• Treat plants before uprooting in the presence of high pest populations.
• Remove and destroy plant debris and crop residues.