How to combat the lychee mite

Several tropical fruits were brought to Brazil during the Portuguese navigation. Already in the 16th century, figs, bananas, star fruit, pomegranates, jackfruit, oranges and mangoes were cultivated in the country. Around 1800, breadfruit was introduced, in 1810 lychee and, more recently, in 1970, kiwi (Lorenzi et al.

From the detailed work of Higgins (1917), “The lychee in Hawaii", information is collected about the transport of lychee in the other direction, that is, from Southeast Asia, across the Pacific, to Hawaii. The author informs that Reports about lychee are found in Chinese writings prior to the Christian era and its origin must be between southern China and Southeast Asia. From there it was introduced long ago to Sri Lanka, India, Taiwan, Australia and Mauritius. It also does reference to its presence in Brazil and the Caribbean. In 1873 the first tree was brought to Hawaii, with the lychee arriving in Florida (Euan) around 1886. In California (Euan) a plant from India was introduced in 1897 In the item on propagation, Higgins informs that the seeds, although they germinate well, have a very short life, losing their germination power in about five days. In other words, the transport of lychee has always taken place through plants and trees.

Higgins also already refers to the presence of an eriophyid mite, observed in Hawaii for the first time in 1816, which destroyed the foliage, stating that the rootstock then used, longan (Dimocarpus longan), was resistant to this mite.

Lychee erinosis has also been known for a long time: since 1912 in India, 1945 in Florida (Euan), 1963 in Bangladesh, 1981 in Australia, 1985 in Taiwan, according to Waite & McAlpine (1992). These authors verified the transport of the lychee erynosis mite, alive, by the honey bee, discussing this in the context of observations of “spontaneous infestations” in inflorescences of orchard plants that were previously free from the pest.

The introduction of lychee in Brazil around 1810 (the 1810 report mentions a large tree, therefore, it had already been cultivated for one to two years) was due to plants free from the erinosis mite, as the culture of this fruit plant expanded for 200 years without any indication of the presence of the erinosis mite, the first report of which occurred in 2008 (Raga et al, 2008), in Limeira orchard, andstate of São Paulo.

Despite the many works published in other regions of the world warning about the damage caused to lychee by the erinose mite and the regulation of the mite as an Absent Quarantine Pest (A1) (Map, Normative Instruction No. 52, November 20, 2007), infested plants were imported without due care. The quarantine measures that could/should have intercepted them were non-existent or ineffective. It is possible that the mite was inadvertently introduced into the country through the illegal importation of propagation material by some reckless, uninformed and unpunished citizen.

Until the introduction of the lychee mite in Brazil, the crop was considered by farmers to be quite resistant to pests and had been expanding in the states of São Paulo, Minas Gerais and Paraná. Currently, the lychee erinosis mite is considered a key pest of the crop. Mite infestations have caused quantitative and qualitative losses in production. In addition to affecting plant development and foliage, mites can directly damage fruits. The application of mite control measures has been essential, which has significantly increased the cost of production. Lychee production in Brazil has fallen drastically in the last five years and this is largely due to lychee erinosis.

Questions now remain. Who will bear the losses caused by the plague in the country, which has been compromising a culture that had been expanding in several states and with excellent prospects? How is Brazil prepared to defend agribusiness, one of its great foundations? Will phytosanitary defense be a utopia until there are investments that really allow a qualitative leap in the system?

At the moment the agricultural sector faces the challenge of controlling another great enemy, the well-known Helicoverpa armigera, and maintain the sustainability and profitability of crops. What can we do to protect ourselves from tiny organisms that also pose important threats to our agriculture?

By Carlos Flechtmann e Denise Navia

(Article in issue 83 of Revista Cultivar Hortaliças e Frutas.)

More information at: "Lychee mite management".