Aculops lycopersici  (Tryon)

Bronze acariosis  

General

• Tiny mite from the group of mites 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 global 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 shelter.

• Susceptible botanical family(s)

• Production areas affected :

• Organs attacked

Symptoms, damage

• Symptoms :
  • Brown to bronze coloring of the leaves (figures 3 and 4), petioles and stems (figure 5) from which the name of this problem originates.
  • Flower abortion (Figure 6).
  • Leaf drying that can lead to the death of plants when the attack is not controlled (figure 7).
  • Corky areas more or less extensive, even cracked on fruits (figures 8 to 12).
• 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 persists on cultivated or uncultivated Solanaceae. The biological cycle lasts one week in tropical conditions and lengthens in cooler climates.
• Dispersion : by the wind, animals and insects moving through 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

• Rather difficult to control because this mite is often detected too late in crops by the first damage it causes (bronze colour).
• Weed the crop and its surroundings.
• Disinfect the greenhouses and the equipment used.
• Control the sanitary quality of the plants before and during their introduction into the culture or shelter.
• Produce the seedlings in a clean shelter . nurseries insect-proof are insufficient to prevent the entry of tan acariosis given their very small size and their mode of dissemination.
  
• Consider  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 treating them locally and the surrounding plants.
• Use a large volume of mixture and with enough pressure to reach 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.