Update: New Pest & Disease Records (20 Aug 14)

Phytoplasmas that do not belong to the apple proliferation group have been found in infected apple trees in Iran © Brad Greenlee (CC BY)
Phytoplasmas that do not belong to the apple proliferation group have been found in infected apple trees in Iran © Brad Greenlee (CC BY)

We’ve selected a few of the latest new geographic, host and species records for plant pests and diseases from CAB Abstracts. Records this fortnight include 2 new phytoplasma species infecting apple trees in Iran,  the first report of Colletotrichum asianum causing anthracnose on Willard mangoes in Sri Lanka and the first report of Groundnut ringspot virus in cucumber fruits in Brazil.

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New plant disease records from CABI scientists in 2011

Pustules of the potato deforming rust, Aecidium cantense, on an African eggplant leaf © Fen Beed, CGIAR

In 2011, CABI scientists helped to discover new occurrences of disease-causing phytoplasmas and fungi in Africa, Asia and Oceania. Our scientists, based in Egham in southeast England, provide the Plantwise diagnostic service free of charge to developing countries to support the plant clinics, which give advice to farmers with plant health problems. They work in collaboration with scientists from other institutions around the world to diagnose diseases that can’t be identified in the country that the diseases are found.

As farmers monitor their crops for pests and diseases, new discoveries are being made all the time. New species of pest are found, known pests pop up in a new place or find homes on new plant species. Increased globalisation has facilitated the spread of many pests; more complex trade and travel networks have led to more opportunities for pests to hitch a ride to a new place. Changes in climate can also change the suitability of regions to pests, leading to a spread to locations not previously threatened. When it has been confirmed that a pest has been found in a new place or on a new plant host, our scientists publish their report in a peer-reviewed journal such as New Disease Reports to communicate their findings to the wider scientific community. The following records are those co-authored by CABI scientists in 2011. Continue reading

How plant diseases attract plant pests

Aster leafhopper – one of the species of sap-sucking bugs that transmits phytoplasma © Whitney Cranshaw, Colorado State University, Bugwood.org

In the same way that mosquitoes transmit the malaria-causing parasite, Plasmodium, between humans, some species of leafhopper transmit phytoplasma bacteria between plants. Phytoplasmas are bacterial pathogens that infect the plant phloem and require sap-sucking bugs to transport them to other plants. Researchers at the John Innes Centre on Norwich Research Park have found that leafhoppers living on plants infected with phytoplasma produced more offspring. This is the first time that a particular protein in the bacteria has been found that reduces the plants’ defensive reactions to pests such as leafhoppers, allowing the bugs to thrive.
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