Tikka Disease in Ground nut

                Groundnut or peanut (Arachis hypogaea L.) is one of the important oilseed crops, grown and consumed wide spread area in the world, especially in tropics and subtropics. It is a Leguminosae crop, 4th important edible oil and 3rd important source of protein in the world. Ground nut has  44 to 50 percent  oil and 25 to 30 percent of protein. India is the second largest producer of groundnuts after China, though it ranks first in terms of area under cultivation. Groundnut is the 3rd important  oilseed produced in India after rapeseed-mustards and soybean.  The crop,  being a nitrogen-fixing crop through through symbiosis,  considered as an important crop to be cultivated rotations all over the country (Desai et al., 1980). On extraction of oil,  ground nuts yield cakes and are considered as important source of manure and cattle feed. Use of  ground nut plants as hay and silage  after pod harvest  can be  source of fodder.    Gujarat state  stands first in its production, where as  Andhra Pradesh is  in area.

                 Like any other crop,   ground nut  also suffers from myriads of constrains.   One important among them is incidences of many diseases especially fungal kind.  Tikka is the one such  fungal disease which accounts for huge yield loss if unattended  timely. It is a leaf spot disease, involves Early and Late leaf spot diseases. Early leaf spot is caused by Cercospora arachidicola Hori, where as late leaf spot by Cercosporidium personatum (Berk. and Curt) Arx (Phaeoisariopsis personata).

                The leaf spot diseases can cause 30 to 70 percent of loss in pod yield and reduction in the kernel quality (Reddy et al., 1997), Besides causing quantitative losses,  diseases are responsible for reduction in protein content and oil recovery (Gupta et al., 1987).

                    Both early and late leaf spot  diseases are characteristics of  appearance of  lesions on  leaf lamina,  leaf petiole   stems and pods. Early leaf spot  occurs as early as one to two month and characteristics of  relatively lighter  brown spots with yellow hallows. Late leaf spots, usually occurs in around two month old crop and affect  flowering and pod formation stage. The same is characteristics of  darker brown spots without any yellow hallow. In both the cases,  lesions coalesce to produce necrotic spots,  leading to  shedding of leaves, affecting photosynthesis.  As a result the crop looses the vigor and tend to produce lesser in number and inferior sized pods.  Prolonged days of high   relative humidity,  accumulation of dew on leaf  surface,  temperature lesser than  20° C do favor the disease incidences. Continuous rainfall or  overhead irrigation which keeps the leaf surface wetting  for a longer period of time also aggrandize the situation. Heavy doses nitrogenous fertilizer and  Magnesium  deficiency also has proved congenial for the disease.  Primary source of  infections is infected seeds and infected plant debris.  Sometimes wind blow and rain flashes acts as carrier of  pathogens. 

Symptoms of Tikka Disease:

Management of Ground nut tikka disease

There are different ways to manage the incidences of tikka disease in ground nut. Integrated approach is best one.

Cultural Method: Cultural methods like crop rotation, removal and destruction debris after harvest, maintaining of proper plant density are the recommended  measures. Cultivation of resistance verities like TNAU CO6, ALR-3 and VRI Gn-2 are preferred. Kopergaon-3 is one such   variety has demonstrated resistance to late leaf spot. Growing the the crop  early in the season may lead to escape severity of disease incidences. Providing enough spacing allows proper aeration, thus helps to maintain optimum humidity. Providing optimum level of watering and less chance of water stagnation helps to easy management of diseases. Destroying of debris is equally  important as they may become source of inoculum. Crop rotation is the another important aspect to be considered to break the consistency of inoculum development.

Biological Control: Extracts from certain plants like neem or pongamia, can be used as a spray. Trichoderma harzianum and Bacillus megaterium have shown promising results in controlling Cercospora leaf spot. Spraying
 of
 Trichoderma
 viride
 (5
 percent)
 and
 Verticillium
 lecanii
(5
percent)
may help in disease control. Neem
leaf
extract
@ 5%,
Neem
oil
 @ 1%,
 neem
 kernel
 extract
@ 3% can
 effectively
 reduce the severity of 
the
disease incidences.

Chemical control: Spray of Chlorothalonil @0.1% , 1kg /ha at 15 days interval has been found effective. Two
sprays
of
Hexaconazole
 (0.2
per
cent),
Carbendazim
 (0.1
 per
cent)
+
Mancozeb
(0.2
per
cent) has effective control the disease. Bavistin
 at
 0.1
 per
 cent,
 followed
 by
 2
 per
 cent
 neem
 leaf
 extract
+
1.0
per
cent
K2O
significantly
reduced
the
severity
of
leaf.