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Agronomy advice, training and product news: keep up with BonAgro in Tanzania.

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Green coffee beans spread out to dry on raised mesh tables on a coffee farm in Tanzania

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Product8 September 2026

BonCuivre 50 WP: preventive protection of coffee against leaf rust

Coffee leaf rust weakens the trees and reduces the following crop. Copper-based BonCuivre 50 WP protects the foliage when it is applied before the disease sets in, at the start of the rains.

Rust appears as yellow-orange powdery spots on the underside of the leaves, which then fall early. Badly affected trees lose vigour and bear less the following season. The disease is favoured by wet weather and heavily bearing trees, especially at lower altitudes.

Copper fungicides act on contact and must be on the leaves before infection: spray preventively at the start of the rainy season, then every three to four weeks depending on disease pressure, covering the underside of the leaves well. Good pruning and balanced nutrition help the trees to cope.

BonCuivre 50 WP, based on copper hydroxide, is available from our network in Tanzania. Always read the label for rate, interval and protective equipment.

Training4 August 2026

Training on safe use for farmer groups, cooperatives and agro-dealers

BonAgro Tanzania offers practical sessions on protective equipment, sprayer calibration, safe storage and empty container management.

Our sessions are held in the field or at the premises of farmer groups and cooperatives, with practical demonstrations: reading the label, choosing and wearing protective equipment, preparing the spray mix and washing after spraying.

Participants practise calibrating a knapsack sprayer, so that the right rate reaches the crop, and triple rinsing empty containers, which recovers the remaining product for the spray tank and makes the container unfit for any other use, especially for food or water.

Groups that would like to host a session can contact us through the online form or at our sales outlets, giving their location and main crops.

Season16 June 2026

Cashew flowering: protect the panicles from powdery mildew

As cashew trees begin to flower in Mtwara and the other growing areas of the south and the coast, powdery mildew and sucking bugs can cause heavy losses. A programme started at panicle emergence protects the crop.

Powdery mildew covers young panicles, flowers and tiny nuts with a white powder: affected flowers dry up and the young nuts drop or stay small. The disease develops during the cool nights of the flowering season, so protection must start early.

Start at panicle emergence and repeat every two to three weeks during flowering, spraying in the cool hours of the day. Sulphur-based BonSoufre 80 WG can be alternated with BonAzox 250 SC (FRAC 11) or BonTebu 250 EW (FRAC 3) to limit the risk of resistance.

Watch also for Helopeltis and coconut bugs on young shoots and nuts: at the first feeding lesions, BonLambda 25 EC can be applied early in the morning or late in the day, outside bee foraging hours. Always read the label before use.

Advice3 March 2026

Rice: control weeds in the first weeks after transplanting

In lowland rice, weeds that emerge with the crop cause the heaviest yield losses. Early post-emergence control and good water management keep fields clean.

Barnyard grass, sedges and broadleaf weeds compete strongly with young rice for light and nutrients. From the Kilombero valley to the rice fields of Mbeya and the Lake Zone, the first four to six weeks after transplanting or sowing are the most critical.

Spray post-emergence while the weeds are young, 15 to 25 days after sowing or transplanting: drain the field before spraying and re-flood it one to three days later, as the label instructs. Well-levelled fields and good water control help to suppress new flushes of weeds.

Bispyribac-sodium, the active ingredient of BonRiz 100 SC, controls the main grass, sedge and broadleaf weeds of rice. BonRiz 100 SC is available from our network in Tanzania. Always read the label before use.

Advice10 February 2026

Lake Zone cotton: protecting squares and bolls

From squaring onwards, bollworms, jassids and aphids threaten cotton in Shinyanga, Mwanza and the neighbouring regions. Regular scouting decides when to spray.

The African bollworm feeds on squares, flowers and young bolls, which then drop or rot. Jassids make the leaf margins turn yellow and curl, and aphids weaken young plants; late in the season, their honeydew can make the lint sticky.

Scout once or twice a week from squaring and spray only when pest counts reach the thresholds recommended by extension services. Bollworm sprays usually fall between flowering and boll formation: alternate BonLambda 25 EC (IRAC 3A), BonEma 19 EC (IRAC 6) and BonChloran 200 SC (IRAC 28). Against jassids and aphids, BonAceta 20 SP belongs to IRAC group 4A.

Calibrate your sprayer before the season, spray in the cooler hours of the day and respect the maximum number of applications given on each label.

Season20 January 2026

Southern Highlands maize: scout for fall armyworm now

Maize planted with the first rains in Iringa and Mbeya is reaching the whorl stage, when fall armyworm does the most damage. Regular scouting lets you act at the right time.

Fall armyworm moths lay their eggs on young maize leaves; the larvae move into the whorl, where they feed and hide. Translucent windows on the leaves, ragged holes and sawdust-like frass are the signs to look for. Damage on young plants has the greatest impact on yield.

Check plants at random across the field twice a week. Spray when fresh damage reaches the threshold recommended by extension services, preferably late in the day, directing the spray into the whorl. BonEma 19 EC and BonChloran 200 SC both act on young larvae.

Alternate insecticide groups between sprays to delay resistance, and keep a record of the products used on each field.

Always read the label before use. Product information is given for guidance only; the label of the product authorised in your country always prevails.

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