Towards a solution to protect endangered mangoes productions in Réunion ?

ALPHATEX, in collaboration with the company HORTIBEL, is currently working to find an answer in the fight against the fruit fly on mango trees, which is currently taking place in Réunion.

Alphatex is specialized in arboriculture and horticulture netting. We propose high quality insect screens to protect crops.
Hortibel is a Reunionese company which supply agricultural producers from this region.

Insect screen to protect mangoes from fruit flies

The fruit fly causes losses for mango producers in Réunion

Following various observations, here are our findings :

The presence of the fruit fly has a strong impact on the harvest of fruit suitable for consumption, it divides by 5 the quantity of mangoes that can be sent to the sales network.

  1. More precisely, these fruit flies are : BACTROCERA ZONATA, CERATITIS CAPITATA and BACTROCERA DORSALIS.

Mango producers manage their crops :

  • Without any biological treatmants against fruit flies.
  • With biocontrols such as pheromons, augmentarium (a tool that was put at the disposal of Reunionese producers to fight against fruit flies), talc…
  • With little to no tree pruning
A fruit fly on a mango.
Fruit fly on mango.

Producers can not and, most of all, do not want to use chemical solutions. ALPHATEX and HORTIBEL have decided to study a mechanical method in order to support existing tools. Therefore, we tried to use nettings to protect mango trees.

Under certains conditions, the Biotex 800 insect screen can prevent fruit flies from deteriorating mangoes.

The Biotex 800 net against fruit fly, a trial with a Réunionese producer

The Biotex netting has great characteristics which can solve mangoes producers’ problems. This net is :

  • Closed enough to prevent fruit flies from going through.
  • Airy enough to lower climatic effects on trees.
  • Very light, which make the installation easier and won’t crush trees.
  • Available in large dimensions, to provide a large area of coverage.
Filet anti-insectes Biotex sur un manguier pour le protéger de la mouche des fruits.

Test carried out in december 2020

The nets were placed on mango trees, the Heidi variety was chosen because its mangoes are very sensitive to the fruit fly. This variety, opposed to the JOSE variety, doesn’t have dried flower stems from the previous year that present a risk and could tear the net.

Trees height does not exceed 3.5 metres. The netting was put on trees when fruits were still green.

The producer did this trial with three replicates :

1st replicate

The net was put in place the 8 of December 2020 and mangoes were harvested the 10 of January 2021.

Results :

  • The producer was able to harvest every Heidi mangoes.
  • There were no mangoes bitten by fly.

2nd replicate

This one was a control row, without net.

Results :

  • Not a lot of mangoes were harvested (around 30%).
  • Most of mangoes were bitten by fruits flies.

3rd replicate

The net was put in place the 8 of December 2020 and mangoes were harvested around the 10 of January.

Results :

  • Every Heidi mangoes were havested.
  • There were no mangoes bitten by flies.

Fighting against fruit flies in Réunion thanks to the Biotex net : results of the trial

Nets characteristics

As you can see of the pictures of this study, nets are wide and not very stretch between trees :

  • For a better wind and rain resistance
  • To make the installation easier

The producer’s working method

The producer had to adapt his working method to be able to use Biotex nets in his orchards :

  • The land was cleared before putting the net, in order to prevent it from tearing apart. The land will be cleared again when the net will be removed.
  • The handle of the fruit picker has been shortened for an easy handling under the net.
  • The fruit transport crates were all placed under the net just before harvesting to avoid repeated lifting of the net.

Optimization

There are still some elements that need optimizations for the use of nets on this type of production.

  • Plans for the installation and the removal of the BIOTEX net.
  • Nets dimensions to best meet the needs of the market.
  • Define trees best size in order to put and remove Biotex net easily.
  • Nets management in cases of strong winds.

It should be noted that this net could also be used against longicorn. However, this use still has to be tested.

If you supply producers who have issues with fruit flies in their mango crops, you can contact us. We’ll gladly help you to find a way to solve this problem. To contact us :

  • Mail : alphatex@alphatex.eu
  • Phone : +33 (0)2 35 56 33 56

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