8 0 PESTS – 8.7 - PROMOTING AND MANAGING NATURAL ENEMIES

 

 ORGANIC FARMING COURSE AGRO-ECONOMY

8 0 PESTS – 8.7 - PROMOTING AND MANAGING NATURAL ENEMIES

 

The natural enemies of pests are other organisms (fungi, bacteria, viruses, insect predators, and insect parasiticides) which kill pest. Therefore, the organic farmer should try to conserve natural enemies already present in the crop environment and enhance their impact. This can be achieved with the following methods:

•       Minimize the application of natural pesticides (chemical pesticides anyway are not per-mitted in organic farming).

•       Allow some pests to live in the field which will serve as food or host for natural enemies.

•       Establish a diverse cropping system (e.g. mixed cropping).

•       Include host plants providing food or shelter for natural enemies (e.g. flowers which adult beneficial insects feed on).

There are many possibilities to enhance floral diversity within and along the boundaries of crop fields:

§  Hedges - Use indigenous shrubs known to attract pest predators and parasitoids by offering nectar, pollen, alternative hosts and/or preys. Most flowering shrub species have this property. However, care should be taken to not use plant species known to be alternative hosts of pests or diseases.

§  Beetle banks - Strips of grass in the neighbourhood of crop fields harbour different natural pest enemy groups like carabids, staphylinid beetles and spiders. In order to lower the risk of weeds and plants known as host plants of crop pests and diseases, one to three native grass species can be sown in strips of 1 to 3 m.

§  Flower strips - Use indigenous flowering plant species known to attract predators and parasitoids by offering nectar, pollen, alternative hosts and/or preys. Most flowering plant species have this property. However, care should be taken not to use alternative hosts of pests or diseases. Three to five native flowering plant species can be sown in well-prepared seed beds, arranged in strips of 1 to 3 m on the boundary of the crop field. After flowering, seeds can be collected to renew the strip or create new ones. 

§  Companion plants - Natural pest enemies can also be attracted by companion plants within a crop. These companion plant species can be the same as used in the flower strips. A few (1 or 2 per 10 m²) flowering companion plants within a crop serve as a ‘service station’ for natural pest enemies.

 

 

KOZI YA KILIMO HAI KILIMO-UCHUMI

8 0 WADUDU – 8.7 - KUKUZA NA KUWASIMAMIA ADUI ASILI

 

Maadui wa asili wa wadudu ni viumbe vingine (fangasi, bakteria, virusi, wadudu wanaokula wadudu, na dawa za kuua wadudu) ambao huua wadudu. Kwa hiyo, mkulima wa kilimo-hai anapaswa kujaribu kuhifadhi maadui wa asili ambao tayari wapo katika mazingira ya mazao na kuongeza athari zao. Hii inaweza kupatikana kwa njia zifuatazo:

• Punguza uwekaji wa viuatilifu asilia (viuatilifu vya kemikali hata hivyo haviruhusiwi katika kilimo hai).

• Ruhusu baadhi ya wadudu kuishi kwenye shamba ambalo litakuwa chakula au mwenyeji wa maadui wa asili.

• Anzisha mfumo wa upandaji miti tofauti (k.m. upandaji miti mchanganyiko).

• Jumuisha mimea mwenyeji inayotoa chakula au makazi kwa maadui wa asili (k.m. maua ambayo wadudu wenye manufaa wazima hula).

Kuna uwezekano mwingi wa kuboresha uanuwai wa maua ndani na kando ya mipaka ya mashamba ya mazao:

 Ua - Tumia vichaka vya kiasili vinavyojulikana kuvutia wadudu waharibifu na vimelea kwa kutoa nekta, chavua, mwenyeji mbadala na/au mawindo. Aina nyingi za vichaka vya maua vina mali hii. Hata hivyo, tahadhari inapaswa kuchukuliwa ili kutotumia aina za mimea zinazojulikana kuwa mwenyeji wa wadudu au magonjwa mbadala.

 Maeneo ya mende - Sehemu za nyasi karibu na mashamba ya mazao huhifadhi makundi mbalimbali ya adui wadudu waharibifu kama vile carabids, mende wa staphylinid na buibui. Ili kupunguza hatari ya magugu na mimea inayojulikana kama mimea mwenyeji wa wadudu na magonjwa ya mazao, spishi moja hadi tatu za nyasi asili zinaweza kupandwa kwenye vipande vya mita 1 hadi 3.

 Vipande vya maua - Tumia spishi za mimea ya kiasili inayotoa maua inayojulikana kuvutia wanyama wanaowinda wanyama wengine na vimelea kwa kutoa nekta, chavua, mwenyeji mbadala na/au mawindo. Aina nyingi za mimea ya maua zina mali hii. Hata hivyo, uangalizi unapaswa kuchukuliwa kutotumia majeshi mbadala ya wadudu au magonjwa. Aina tatu hadi tano za mimea asilia zinazotoa maua zinaweza kupandwa kwenye vitanda vya mbegu vilivyotayarishwa vyema, vikiwa vimepangwa kwa vipande vya mita 1 hadi 3 kwenye mpaka wa shamba la mazao. Baada ya maua, mbegu zinaweza kukusanywa ili kufanya upya ukanda au kuunda mpya.

 Mimea shirikishi - Maadui wa wadudu wa asili wanaweza pia kuvutiwa na mimea shirikishi ndani ya zao. Aina hizi za mimea shirikishi zinaweza kuwa sawa na kutumika katika vipande vya maua. Mimea michache (1 au 2 kwa kila m2 10) inayochanua maua hutumika kama 'kituo cha huduma' kwa maadui wa asili wa wadudu.