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When it comes to talking about disease-related issues in greenhouse crops, one point of confusion is often WHICH pathogens CAN be transmitted by water. Some are obvious – we all know Pythium is water-borne. But what about other culprits, like Fusarium or Erwinia? Should you worry about these in your recirculating water?

“Water-borne” fungi
You may have heard the term “water-borne” when discussing irrigation water and disease risks from Fungi, but aren’t sure exactly which pathogens it includes.

Generally, there are two types of pathogens we can consider as “water borne” fungi. The first – and most classic definition – are pathogens that are actually motile in water (i.e. produce swimming structures). This includes Pythium and Phytopthora. Both of these diseases are technically classified as “water molds”, being more closely related to algae than to fungi, though they look very much like fungi. They are well adapted to an aquatic environment and can live where irrigation water is stored (cisterns, ponds) for long periods.

Fungicides work by stopping or inhibiting fungal growth, sporulation or germination of spores. Different fungicides act on different stages of the fungal lifecycle and not all fungicides are effective against all fungi. Resistance occurs when a pathogen that was once sensitive to a fungicide is no longer sensitive (not controlled). Managing the use of fungicides and fungicide resistance in farms is important and can be achieved with planning.

Protectant, curative and eradicant products
Fungicides are categorised by the stage of the disease cycle they target. Although the life cycles and biology of pathogens as a whole are very diverse, the disease cycle can be split into the following generalised stages:

Infection (penetration of the host plant)
Colonisation (multiplication of the pathogen within the local area of infection in the plant before symptoms occur)

Symptom expression (visual signs of disease)
Spore production and spread (normally occurs multiple times per year, depending upon the pathogen and environmental conditions)

Flower farmers in Kenya are being forced to throw away a quarter of their produce due to a drop in airline traffic in the wake of restrictions imposed on rival carriers to protect Kenya Airways.

Kenya Flower Council (KFC), the lobby for large-scale flower farms, says they need freight capacity of at least 5,000 tonnes a week against the 3,500 tonnes available. The government has been reluctant to allow Ethiopian Airlines, for instance, to increase its capacity from Jomo Kenyatta International Airport (JKIA).

“On average our members are dumping flowers equivalent to 25 percent of their produce because of the limited cargo capacity,” said Clement Tulezi, chief executive of the Kenya Flower Council.

Mealybugs pose a serious threat to growers in warmer climates as they can significantly reduce the productivity and yield of greenhouse crops. But lessons-learnt from greenhouse rose farms in Kenya demonstrate that it is possible to manage Mealybugs when the right tactics are deployed, such as early intervention supported by an effective scouting system, writes Edwin Kiptarus and Simon Kihungu

Mealybugs1Mealybugs have taken on a renewed significance with the recent arrival and rapid spread in Kenya of the Papaya mealybug, Paracoccus marginatus. Although not the same species as the Coffee mealybug, Planococcus kenyae, generally found on roses in Kenya, both are quarantine pests that have the potential to spread viruses along fresh cut flower pathways. Other Species of Mealybugs that affects ornamentals are: Common examples include the long tailed mealybug (Pseudococcus longispinus), which has characteristically long waxy filaments that protrude from the end of the abdomen, and the obscure mealybug (Pseudococcus viburni), which also has waxy filaments, but they are much shorter in comparison to the longtailed mealybug. Citrus mealybug (Planococcus citri), lacks any waxy filaments and has a gray stripe that extends the length of the body. The differences are shown in the image below:

mangoes1Makueni is the leading county in mango production contributing up to 31 per cent of the total fruits that Kenya produces. “Right now the amount exported is two per cent of the total production of 184,000 tonnes produced annually, which is a small fraction,” said Robert Kisyula, the then CEC Agriculture, Makueni.

That mangoes are critical to the economy of Makueni County, is not in doubt. What is worrying is that the devolved unit only exports a paltry two per cent to the world market, missing out on lucrative global business.

Part of the reason for a slow uptake on the export market was because of a selfimposed ban by Kenya in 2010 after experiencing a bout of mango fruit fly that risked Kenya’s produce being banned in Europe, which is its main market before the moratorium. “It was easier to pull out ourselves than being banned by markets in Europe. We hope that we will be able to reopen the EU market this year,” he said.

Ruud KnorrIn the run-up to Mother’s Day, Royal FloraHolland could not only report on the good turnover on our market place, but could even report a week record turnover of over 170 million euros. This is partly thanks to the clock. The average price of cut flowers went through the ceiling. The share of the clock has declined in small steps in recent years to 40% last year. But cut flowers are still for the most part traded on the clock. The clock share of cut flowers in terms of turnover is 60% and in terms of volume 54%. This shows that the prices for cut flowers are higher on the clock than in the direct streams.

Estelle MoreauUPL Ltd has continued to deliver successful product innovations. This time they organised a very successful virtual training on Vacciplant, an innovative Biofungicide against powdery mildew in Ornamental crops and Snowpeas. Timely and almost audio-recorded voice of Lara Ramaekers, a UPL Biosolutions Specialist, greeted the air as she took growers through the innovation.

Speaking to the growers Lara asked, “Have you ever thought of protection against powdery mildew without residue?” Adding, “We are discussing the newest technologies in protection against powdery mildew and other causal pathogens. It allows the grower to reduce the number of active ingredients used, achieve better.

Key Benefits
Through the Vaccine action, Vacciplant prompts the plant to fight against the diseases. The product is better used preventively. Lara told the growers that the product has control of various fungal and bacterial diseases with zero residue (0 days PHI). The product poses minimal risk of development of resistance. She confirmed that the product is compatible with both conventional and other biological products. It has no harm to any beneficial organisms and has a unique mode of action. (FRAC Group P4). The product has been approved for organic farming by Ecocert. Vacciplant is also a great tool for successful Integrated Pest Management programs. It is one of the best alternatives for the most demanding food chains and organic growers. It is a complimentary solution to conventional plant protection products.