8 1 NATURAL PESTICIDES – 8.10 - RELEASING NATURAL ENEMIES

 

ORGANIC FARMING COURSE AGRO-ECONOMY

8 1 NATURAL PESTICIDES – 8.10 - RELEASING NATURAL ENEMIES

If populations of natural enemies present in the field are too small to sufficiently control pests, they can be reared in a laboratory or rearing unit. The reared natural enemies are released in the crop to boost field populations and keep pest populations down. There are two approaches to biological control through the release of natural enemies:

•     Preventive release of the natural enemies at the beginning of each season. This is used when the natural enemies could not persist from one cropping season to another due to unfavourable climate or the absence of the pest. Populations of the natural enemy then establish and grow during the season.

•     Releasing natural enemies when pest populations start to cause damage to crops (Figure 8-9). Pathogens are usually used in that way, because they cannot persist and spread in the crop environment without the presence of a host (“pest”). They are also often inexpensive to produce.

 

TEXT in the picture:

•     releasing beneficial insects

•     cards with trichogramma eggs: against maize fruitborer

•     using antaginic microbes

•     BACTERIA: Bazillus thuringensis àagainst catarpillars, beetles, mosquito etc.

•     VIRUSES: NPV àagainst catarpillar

•     FUNGI: Beauveria bassiana àagainst corn boreres

•     NEMATODES: Steinernema carpocapsae -à against cutworms

KOZI YA KILIMO HAI KILIMO-UCHUMI

8 1 DAWA ASILI ZA WAdudu – 8.10 - KUWAACHA MAADUI WA ASILI

Ikiwa idadi ya maadui wa asili waliopo shambani ni ndogo sana kudhibiti wadudu vya kutosha, wanaweza kukuzwa katika maabara au kitengo cha ufugaji. Maadui asilia waliolelewa hutolewa katika zao ili kuongeza idadi ya wadudu na kupunguza idadi ya wadudu. Kuna njia mbili za udhibiti wa kibaolojia kupitia kutolewa kwa maadui asilia:

• Kinga ya kutolewa kwa maadui wa asili mwanzoni mwa kila msimu. Hii inatumika wakati maadui wa asili hawakuweza kuendelea kutoka msimu mmoja wa mazao hadi mwingine kutokana na hali mbaya ya hewa au kutokuwepo kwa wadudu. Idadi ya adui wa asili huanzisha na kukua wakati wa msimu.

• Kuwaachilia maadui wa asili wakati idadi ya wadudu inapoanza kusababisha uharibifu wa mazao (Mchoro 8-9). Pathogens kawaida hutumiwa kwa njia hiyo, kwa sababu hawawezi kuendelea na kuenea katika mazingira ya mazao bila kuwepo kwa mwenyeji ("wadudu"). Pia mara nyingi ni gharama nafuu kuzalisha.

TEXT kwenye picha:

• kutoa wadudu wenye manufaa

• kadi zenye mayai ya trichogramma: dhidi ya mzaa matunda wa mahindi

• kutumia vijidudu vya antaginic

• BACTERIA: Bazillus thuringensis dhidi ya catarpillar, mende, mbu n.k.

• VIRUSI: NPV dhidi ya catarpillar

• FANGASI: Beauveria bassiana dhidi ya vipekecha-mahindi

• NEMATODES: Steinernema carpocapsae - dhidi ya minyoo