8 1 NATURAL PETICIDES – 8.17 - OTHER PRACTICES FOR DISEASE CONTROL

 

  

ORGANIC FARMING COURSE AGRO-ECONOMY

8 1 NATURAL PETICIDES – 8.17 - OTHER PRACTICES FOR DISEASE CONTROL  

 

Ø  Sulphur is mostly used against plant diseases like powdery mildew, downy mildew and other diseases. The key to its efficacy is that it prevents spore germination. For this reason, it must be applied prior to disease development for effective results. Sulphur can be applied as a dust or in liquid form. It is not compatible with other pesticides. Lime-sulphur is formed when lime is added to sulphur to help it penetrate plant tissue. It is more effective than elemental sulphur at lower concentrations. However, the odour of rotten eggs usually discourages its use over extensive fields.

Ø  Bordeaux mixture (Copper sulphate and lime) has been successfully used for over 150 years, on fruits, vegetables and ornamentals. Unlike sulphur, Bordeaux mixture is both fungicidal and bactericidal. As such, it can be effectively used against diseases such as leaf spots caused by bacteria or fungi, powdery mildew, downy mildew and various anthracnose pathogens. The ability of Bordeaux mixture to persist through rains and to adhere to plants is one reason it has been so effective. Bordeaux mixture contains copper sulphate, which is acidic, and neutralized by lime (calcium hydroxide), which is alkaline. 

Recommendations to farmers on preparation of Bordeaux mixture: Bordeaux mixture comes in several formulations. One of the most popular, effective and least phytotoxic formulations for general use is the following formulation: Mix 90 g of blue copper sulphate with 4,5 L of water (in a non-metallic container). In another non-metallic container, mix 125 grams of slaked lime with 4.5 litres of water. Stir both, mix both solutions, and stir again. This formulation was developed in recognition of the fact that copper, like sulphur, is phytotoxic and that the level of toxicity is related to the age of plant tissue being treated. Application of Bordeaux during hot weather (above 29,5° C or 1,5° C) may cause yellowing and leaf drop. Additionally, leaf burn can occur if it rains soon after a Bordeaux application. Care should be taken when applying this fungicide to young, tender leaves of fruit trees. Do not apply Bordeaux mixture to corn or sorghum, which are described as copper-sensitive plants. There are other, very common and cheap copper formulations available: copper hydroxide and copper oxychloride. They are accepted in organic farming provided that the number of applications is strictly followed and a proper soil amendment is observed to prevent copper accumulation in the soil. 

Ø  Acidic clays have a fungicidal effect due to aluminium oxide or aluminium sulphate as active agents. They are used as an alternative to copper products but, are often less efficient.

Ø  Milk has also been used against blights, mildew, mosaic viruses and other fungal and viral diseases. Spraying every 10 days with a mixture of 1 L of milk to 10 to 15 L of water is effective.

Ø  Baking soda has been used to control mildew and rust diseases on plants. Spray with a mixture of 100 g of baking or washing soda with 50 g of soft soap. Dilute with 2 L of water. Spray only once and leave as long gaps as possible (several months). Do not use during hot weather and test the mixture on a few leaves because of possible phytotoxic effects.

Many plant extracts are known to have fungicidal effects. Onion and garlic are effective against many diseases such as mildew and fungal and bacterial diseases. Mexican and African marigold act as a crop “strengthened” to help potatoes, beans, tomatoes and peas resist fungal diseases such as mildew. The leaves of pawpaw (Carica papaya) and sweet basil have a general fungicidal effect. Many other plant species are known to have fungicidal effects. Traditional knowledge might be of help to amend the range of plant extracts in each region.

 

KOZI YA KILIMO HAI KILIMO-UCHUMI

8 0 WADUDU – 8.17 - TABIA NYINGINE ZA KUDHIBITI MAGONJWA

 Sulfuri hutumika zaidi dhidi ya magonjwa ya mimea kama vile ukungu, ukungu na magonjwa mengine. Ufunguo wa ufanisi wake ni kuzuia kuota kwa spore. Kwa sababu hii, lazima itumike kabla ya maendeleo ya ugonjwa kwa matokeo ya ufanisi. Sulfuri inaweza kutumika kama vumbi au katika hali ya kioevu. Haiendani na dawa zingine za wadudu. Chokaa-sulphur huundwa wakati chokaa kinaongezwa kwenye sulfuri ili kusaidia kupenya tishu za mimea. Ni bora zaidi kuliko sulfuri ya msingi k

atika viwango vya chini. Hata hivyo, harufu ya mayai yaliyooza kwa kawaida huzuia matumizi yake juu ya mashamba makubwa.

 Mchanganyiko wa Bordeaux (Copper sulphate na chokaa) umetumika kwa mafanikio kwa zaidi ya miaka 150, kwenye matunda, mboga mboga na mapambo. Tofauti na salfa, mchanganyiko wa Bordeaux ni wa kuua na kuua bakteria. Kwa hivyo, inaweza kutumika kwa ufanisi dhidi ya magonjwa kama vile madoa ya majani yanayosababishwa na bakteria au fangasi, ukungu wa unga, ukungu na vimelea mbalimbali vya magonjwa ya anthracnose. Uwezo wa mchanganyiko wa Bordeaux kuendelea kupitia mvua na kuambatana na mimea ni sababu moja umekuwa mzuri sana. Mchanganyiko wa Bordeaux una sulphate ya shaba, ambayo ni tindikali, na haipatikani na chokaa (hidroksidi ya kalsiamu), ambayo ni ya alkali.

Mapendekezo kwa wakulima juu ya utayarishaji wa mchanganyiko wa Bordeaux: Mchanganyiko wa Bordeaux huja katika uundaji kadhaa. Mojawapo ya uundaji maarufu zaidi, wenye ufanisi na mdogo wa phytotoxic kwa matumizi ya jumla ni uundaji ufuatao: Changanya 90 g ya sulphate ya shaba ya bluu na 4,5 L za maji (katika chombo kisicho na metali). Katika chombo kingine kisicho na metali, changanya gramu 125 za chokaa kilichopigwa na lita 4.5 za maji. Koroga zote mbili, changanya suluhu zote mbili, na ukoroge tena. Muundo huu ulitengenezwa kwa kutambua ukweli kwamba shaba, kama salfa, ina sumu ya fitoksi na kwamba kiwango cha sumu kinahusiana na umri wa tishu za mmea kutibiwa. Uwekaji wa Bordeaux wakati wa joto (zaidi ya 85° F au 30° C) unaweza kusababisha manjano na kushuka kwa majani. Zaidi ya hayo, kuchomwa kwa majani kunaweza kutokea ikiwa mvua inanyesha mara baada ya maombi ya Bordeaux. Uangalifu unapaswa kuchukuliwa wakati wa kutumia dawa hii ya kuvu kwa majani machanga na laini ya miti ya matunda. Usitumie mchanganyiko wa Bordeaux kwenye mahindi au mtama, ambayo inaelezwa kuwa mimea inayoguswa na shaba. Kuna uundaji mwingine, wa kawaida sana na wa bei nafuu wa shaba unaopatikana: hidroksidi ya shaba na oksikloridi ya shaba. Zinakubalika katika kilimo-hai mradi tu idadi ya maombi inafuatwa kikamilifu na marekebisho sahihi ya udongo yanazingatiwa ili kuzuia mkusanyiko wa shaba kwenye udongo.

 Udongo wenye asidi huwa na athari ya kuua ukungu kutokana na oksidi ya alumini au salfa ya alumini kama mawakala hai. Zinatumika kama mbadala kwa bidhaa za shaba lakini, mara nyingi hazifanyi kazi vizuri.

 Maziwa pia yametumika dhidi ya ukungu, ukungu, virusi vya mosaic na magonjwa mengine ya fangasi na virusi. Kunyunyizia kila siku 10 kwa mchanganyiko wa lita 1 ya maziwa hadi lita 10 hadi 15 za maji ni nzuri.

 Soda ya kuoka imetumika kudhibiti magonjwa ya ukungu na kutu kwenye mimea. Nyunyiza na mchanganyiko wa 100 g ya kuoka au kuosha soda na 50 g ya sabuni laini. Punguza na 2 L ya maji. Nyunyizia dawa mara moja tu na uache mapengo marefu iwezekanavyo (miezi kadhaa). Usitumie wakati wa hali ya hewa ya joto na jaribu mchanganyiko kwenye majani machache kwa sababu ya athari zinazowezekana za phytotoxic.

Extracts nyingi za mimea zinajulikana kuwa na athari za fungicidal. Vitunguu na kitunguu saumu ni bora dhidi ya magonjwa mengi kama vile ukungu na magonjwa ya fangasi na bakteria. Marigold ya Mexico na Afrika hufanya kama zao "iliyoimarishwa" kusaidia viazi, maharagwe, nyanya na mbaazi kupinga magonjwa ya ukungu kama vile ukungu. Majani ya papai (Carica papai) na basil tamu yana athari ya jumla ya kuvu. Aina nyingine nyingi za mimea zinajulikana kuwa na athari za fungicidal. Maarifa ya kimapokeo yanaweza kusaidia kurekebisha aina mbalimbali za dondoo za mimea katika kila eneo.