Sa­vanna in­vader

Farmer's Weekly (South Africa) - - Archive -

17 YEARS AGO

Sour prickly pear has a neg­a­tive eco­nomic im­pact for landown­ers as it ren­ders vi­able graz­ing and agri­cul­tural land use­less. Here are some tips on how to get rid of it.

Sour prickly pear in­vades dry sa­vanna and spreads pri­mar­ily by seeds, and se­condly by veg­e­ta­tive means.

Fruits are eaten by many an­i­mals, mainly ba­boons, mon­keys, an­te­lope, birds and ele­phants.

Hu­mans are the main dis­trib­u­tors of the weed, as they are of­ten planted in gar­dens from where they spread.

Full name: Aus­tralian pest pear, sour prickly pear, su­ur­turksvy, or Opun­tia stricta.

Ori­gin: Florida, United States. De­scrip­tion:

• Spread­ing, highly branched suc­cu­lent shrub (0,5m to 1,5m high). • Clado­des are green to blue-green and flat­tened (longer than broad). • Spines are up to 40mm long, usu­ally one or two in a group or ab­sent.

• Flow­ers are yel­low and showy (in­tro­duced as an or­na­men­tal), up to 70mm long. • Club-shaped fruit are red, turn­ing pur­ple out­side and in­side, an im­por­tant iden­ti­fi­ca­tion fea­ture (the deep-pur­ple juice is of­ten used as a food colourant).

Flow­er­ing takes place from Novem­ber to Jan­uary.

TREAT­MENT OP­TIONS

Prickly pear is con­trolled ef­fec­tively by a newly in­tro­duced, hostadapted bio­type of cochineal. For dense in­fes­ta­tions, only bio­con­trol is ef­fec­tive. En­sure that the stricta bio­type of the prickly pear cochineal is present in ev­ery in­fes­ta­tion of the Aus­tralian pest pear. Con­tact your pro­vin­cial of­fice of the Direc­torate of Agri­cul­ture, Land and Re­source Man­age­ment to es­tab­lish where the near­est cochineal-in­fested leaf­pads are, and care­fully place these into the cen­tre of the plant in­fes­ta­tion (where they will be pro­tected from wind and rain).

Once the in­sects have started to mul­ti­ply, their dis­per­sal can be ac­cel­er­ated by car­ry­ing the in­fested lead­pads to dis­tant plants.

No chem­i­cal con­trol is re­quired once cochineal has been es­tab­lished in all ar­eas where Aus­tralian pest pear is present.

Be­fore ap­ply­ing her­bi­cides, it is im­por­tant to read in­struc­tions care­fully.

RIGHT: Th­e­sour­prickly pearisan­in­va­sive speci­esthat­can ren­der­a­gri­cul­tural lan­duse­less. This pho­to­graph ac­com­pa­nied the ar­ti­cle in our 19 Oc­to­ber 2001 is­sue.

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