Guava (psidium guajava) is the most important fruit and cultivated in the tropic and sub tropic regions and due to wide adoptability of different soil and climatic conditions it has attained commercial importance in tropical and sub-tropical regions. It is native to tropical America (Mexico to Peru) or believed to be originated from this. At present time it is mainly produced in south Asian countries, including Pakistan, India, Cuba and Brazil.

It is grown in all provinces of Pakistan under an area of 58.5 thousand hectares with almost production of 468.3 tones. Punjab seems to leading growing region of Pakistan it includes Lahore, Kasur, Sangla hills, Sheikhupora, Shariqpur and Gujranwala regions. But the full economic potential of the crops is not realized due to lack of required focus on the cultivation technologies, handling, disease managemental strategies, processing and packing. But now a day all the strategies have been adopted in Pakistan for the guava production but in front of a newly emerged disease it seems to be wasted and this disease is so called guava decline.

This disease is a major threat and it become the worst enemy of this fruit and reported from all growing regions of Pakistan. Many research institutes have received the projects on this emerging disease but still we have no progress and due to lack of research it is getting more severe. Now a day decline problem is becoming more common and severe in all orchards of Pakistan. The average disease incidence should be varied with various verities of guava. A high yield reduction from 8920 kg per hectare to 8223 kg per hectares is reported in 2003-2004. It’s a big loss for a country where guava occupies the third position in term of area after citrus and fourth position in term of production after citrus.

In initial stage of this disease wilting and yellowing of leaves occurs and later on complete defoliation should happens. The development of fruits on such kind of trees ceases or doesn’t happen. Fruits of such trees become dry and wrinkled. We can identify easily from the above given symptoms that this tree is infected from decline disease. Guava decline is a serious disease and different pathogens have been reported in guava rhizosphere. Different types of fungi species have been reported from different regions of Pakistan but the main causing agent of this disease is B. theobromae followed by other fungi which are C. gloesporioides, F. solani, Helminthosporium spp., Phythophythora parasitica, F. oxysporum and C. lunata. B. theobromae is a soil born fungus and causing a number of diseases in both field and storage conditions. More than 280 plant species are susceptible to this pathogen. But in Pakistan it has been reported from 50 species of plants. It is spreads by poor handling of plant during shifting and due to poor managemental strategies like intercropping etc. no one denies the lethalness of this disease but we can control this disease by adopting possible solutions include some managemental strategies and by using different type of fungicides.

Managemental strategies:

By adopting the following managemental strategies we can control guava decline. Most important are as follow.

Proper field sanitation should be done on proper time so that inoculums of the pathogen reduce to minimum. Burn the extra waste material from the field. Don’t flood the water to the field during irrigation it may result into the shifting of disease from one plant to other plants. Avoid intercropping especially those plants which are susceptible against the soil born fungi. Remove the diseased plants from the field. If inoculums spreads all over the rhizosphere in orchard than soil shifting also a valuable thing but it is so expensive for an average farmer.

By using some fungicides we can minimize the prevalence of the pathogen but it’s a last option when all measure fails and we have no option other than chemicals. Most important fungicides which show batter results against B. theobromae includes diathane M- 45 @ 2g L-1, alliete and carbendazim as same dose for all fungicides.

Carbendazim show more batter results as it inhibits the growth of fungus and stop the pathogen to further penetration to the plant body. So these are all the preventive measures if we adopt on time than it would help us otherwise it results into big loss of yield.

It’s an alarming condition in Pakistan and spread day by day in whole Pakistan and our researchers are unaware of this alarming situation. If certain preventive measures has not adopted against this disease than it may results in collapse of guava fruit in Pakistan.

GuavaThis article is collectively authored  by Khizar Razzaq1*and Sundas Hanif1, Tanzeel Asim2 and Kashif Naveed3_1Department of plant pathology, University of Agriculture Faisalabad.