International Year of Plant Health (Part 3): How much is it costing commercial farmers?

22 July 2020

According to Dr Trudy Paap, "Avocado trees are among the most susceptible agricultural crop trees to PHSB infestation and Fusarium disease. This is based on experiences in California and Israel."

While infestation of backyard avocado trees has been confirmed in Sandton and Knysna, to date the PSHB has not yet been observed in commercial avocado orchards in South Africa (Van den Berg et al 2019).

 

PSHB affecting a commercial avocado tree

Tree gore from the borer

The only commercial crop on which the PSHB has been detected to date is pecan, though early indications suggest the impact on this tree species may not be severe. Other fruit trees in private gardens on which it has been found include lemon, orange, guava, peach, and grapevine. At this point, however, there is no evidence suggesting that the PSHB poses a threat to these crops, but producers should carefully monitor and report any infestations.

PSHB affecting a pecan nut tree and forming its galleries within the trunk.

The polyphagous shot hole borer is nuts about pecan trees.

In addition to agriculture, commercial forestry is another sector that is concerned. We have only found small numbers of roadside wattle trees with PSHB infestations in the Southern Cape, with a single roadside eucalyptus tree infested in Sandton. No trees in commercial plantations, including pines, have been detected with the PSHB in South Africa.

The polyphagous shothole borer is affecting pecan nut and avocado farmers in South Africa